Bài 9: Mảng trong Java!

[tuannv.phuongdongland001]

• package baitap;
• import java.util.scanner;
• public class bai1 {
• public static void main(string[] args) {
• int a, i;
• scanner nhapdulieu = new scanner(system.in);
• system.out.print("so sinh vien: ");
• a = nhapdulieu.nextint();
• nhapdulieu.nextline();
• string arrstring[] = new string[a];
• if (a > 0) {
• for (i = 0; i < a; i++) {
• system.out.println("nhap ten sinh vien thu " +i);
• arrstring[i] = nhapdulieu.nextline();
• }
• system.out.println("nhap ten sinh vien can tim ");
• string ten = nhapdulieu.nextline();
• int x=0;
• for(i=0;i<a;i++)
• {
• if(ten.equals(arrstring[i]))
• x=x+1;
• }
• if(x>0)
• system.out.println("ten "+ten+" co trong danh sach");
• else
• system.out.println("ten "+ten+" khong co trong danh sach");
• }
• else{
• system.out.println("nhap so sinh vien lon hon 0");
• }
• }
• }

cho mình hỏi chỗ dòng số 10. nhapdulieu.nextline(); là sao ah. mình không thấy mối liên quan của nó trong đoạn code. mà bỏ đi thì code lại chạy lỗi.

[thanhpho722]

bai 1:

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import java.util.arrays;
import java.util.scanner;
public class bai1 {
 
    public static void main(string[] args) {
        timkiem();
       
 
    }
 
    public static int nhapsosv() {
        system.out.print("so sv: ");
        scanner input = new scanner(system.in);
        boolean check = true;
        int n = 0;
        while (check) {
            try {
                n = input.nextint();
                if (n > 0) {
                    check = false;
                } else {
                    system.out.println("so luong sv phai >0, nhap lai!");
                    input.nextline();
                }
            } catch (exception e) {
                system.out.println("so sv phai la so nguyen, nhap lai!");
                input.nextline();
            }
        }
        return n;
    }
 
    public static string[] nhapdanhsach() {
        scanner input = new scanner(system.in);
        int n = nhapsosv();
        system.out.println("nhap ho va ten sv:");
        string[] hoten = new string[n];
        int i = 0;
        while (i < n) {
            system.out.print(i + 1 + ". ");
            hoten[i] = xoaspace(input.nextline());
            i++;
        }
        return hoten;
    }
 
    public static void timkiem() {
        scanner input = new scanner(system.in);
        string[] hoten = nhapdanhsach();
        system.out.print("nhap ten sv can tim: ");
        string ten = xoaspace(input.nextline());       
        system.out.println();
        int chiso = arrays.aslist(hoten).indexof(ten);
        if (chiso != -1) {
            system.out.println("note: sinh vien \"" + ten + "\" co trong danh sach, stt: " + (chiso + 1));
        } else {
            system.out.println("note: sinh vien \"" + ten + "\" khong co trong danh sach!");
        }
 
    }
 
    public static string xoaspace(string str) {
        str = str.replaceall("\\s+", " ");
        str = str.replaceall("^\\s+|\\s+$", "");
        return str;
    }
}

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bai 2:

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import java.util.arrays;
import java.util.scanner;
public class bai2 {
 
    public static void main(string[] args) {
        sapxep();
    }
 
    public static int nhapso() {
        int n = 0;
        scanner input = new scanner(system.in);
        boolean check = true;
        while (check) {
            try {
                n = input.nextint();
                check = false;
            } catch (exception e) {
                system.out.println("chi duoc nhap so, nhap lai!");
                input.nextline();
            }
        }
        return n;
    }
 
    public static int[] nhapdayso() {
        system.out.print("so phan tu cua day so: ");
        int n = nhapso();
        system.out.println("nhap day so: ");
        int[] dayso = new int[n];
        int i = 0;
        while (i < n) {
            dayso[i] = nhapso();
            i++;
        }
        return dayso;
    }
 
    public static void sapxep() {       
        int[] dayso=nhapdayso();
        system.out.println("day so da sap xep la:");
        arrays.sort(dayso);
        for(int i=0;i<dayso.length;i++){
            system.out.println(dayso[i]);
        }
    }
 
   
}

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bai 3:

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import java.util.scanner;
 
public class bai3 {
 
    public static void main(string[] args) {
        congmatran();
    }
 
    public static int nhapkichco() {
        int n = 0;
        scanner input = new scanner(system.in);
        boolean check = true;
        while (check) {
            try {
                n = input.nextint();
                if (n < 0) {
                    system.out.println("kich thuong mang phai la so >0, nhap lai!");
                    input.nextline();
                } else {
                    check = false;
                }
            } catch (exception e) {
                system.out.println("chi duoc nhap so, nhap lai!");
                input.nextline();
            }
        }
        return n;
    }
 
    public static int nhapaij() {
        int n = 0;
        scanner input = new scanner(system.in);
        boolean check = true;
        while (check) {
            try {
                n = input.nextint();
                check = false;
            } catch (exception e) {
                system.out.println("chi duoc nhap so, nhap lai!");
                input.nextline();
            }
        }
        return n;
    }
 
    public static int[][] nhapmatran(int m, int n) {
        int[][] matran = new int[m][n];
        int i = 0;
        while (i < m) {
            int j = 0;
            while (j < n) {
                system.out.print("a[" + i + "][" + j + "]: ");
                matran[i][j] = nhapaij();
                j++;
            }
            system.out.println();
            i++;
        }
        return matran;
    }
 
    public static void congmatran() {
        system.out.print("nhap so hang: ");
        int m = nhapkichco();
        system.out.print("nhap so cot: ");
        int n = nhapkichco();
 
        system.out.println("nhap ma tran 1: ");
        int[][] matran1 = nhapmatran(m, n);
        system.out.println("nhap ma tran 2: ");
        int[][] matran2 = nhapmatran(m, n);
 
        system.out.println(" tong 2 ma tran la:");
        int i = 0;
        while (i < m) {
            int j = 0;
            while (j < n) {
                system.out.print((matran1[i][j] + matran2[i][j] + " "));
                j++;
            }
            system.out.println();
            i++;
        }
 
    }
}

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[malinhdang]

mọi người ơi xem giúp mình bài 3 tại sao lại báo lỗi ở dòng code cuối cùng này với. thank nhiều!
bài 3:
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[color=#000000]
package javabasic[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]util[/color][color=#007700].[/color][color=#0000bb]scanner[/color][color=#007700];public class [/color][color=#0000bb]manghaichieu[/color][color=#007700]{    public static [/color][color=#0000bb]int nhap[/color][color=#007700](){        [/color][color=#0000bb]scanner input[/color][color=#007700]=new [/color][color=#0000bb]scanner[/color][color=#007700]([/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]in[/color][color=#007700]);        [/color][color=#0000bb]boolean bl[/color][color=#007700]=[/color][color=#0000bb]false[/color][color=#007700];        [/color][color=#0000bb]int n[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];        while(![/color][color=#0000bb]bl[/color][color=#007700]){            try{                [/color][color=#0000bb]n[/color][color=#007700]=[/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextint[/color][color=#007700]();                [/color][color=#0000bb]bl[/color][color=#007700]=[/color][color=#0000bb]true[/color][color=#007700];            }            catch([/color][color=#0000bb]exception e[/color][color=#007700]){                [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"moi ban nhap lai:"[/color][color=#007700]);                [/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();            }        }        return([/color][color=#0000bb]n[/color][color=#007700]);    }    public static [/color][color=#0000bb]void matrana[/color][color=#007700]([/color][color=#0000bb]int m[/color][color=#007700],[/color][color=#0000bb]int n[/color][color=#007700]){        [/color][color=#0000bb]scanner input[/color][color=#007700]=new [/color][color=#0000bb]scanner[/color][color=#007700]([/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]in[/color][color=#007700]);        [/color][color=#0000bb]int [/color][color=#007700][][][/color][color=#0000bb]mta[/color][color=#007700]=new [/color][color=#0000bb]int[/color][color=#007700][[/color][color=#0000bb]m[/color][color=#007700]][[/color][color=#0000bb]n[/color][color=#007700]];        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"+cac phan tu cua ma tran a:"[/color][color=#007700]);        for([/color][color=#0000bb]int i[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]<[/color][color=#0000bb]m[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]++){            for([/color][color=#0000bb]int j[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]j[/color][color=#007700]<[/color][color=#0000bb]n[/color][color=#007700];[/color][color=#0000bb]j[/color][color=#007700]++){                [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"a("[/color][color=#007700]+[/color][color=#0000bb]i[/color][color=#007700]+[/color][color=#dd0000]","[/color][color=#007700]+[/color][color=#0000bb]j[/color][color=#007700]+[/color][color=#dd0000]")="[/color][color=#007700]);                [/color][color=#0000bb]mta[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]][[/color][color=#0000bb]j[/color][color=#007700]]=[/color][color=#0000bb]nhap[/color][color=#007700]();            }        }        for([/color][color=#0000bb]int k[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]k[/color][color=#007700]<[/color][color=#0000bb]m[/color][color=#007700];[/color][color=#0000bb]k[/color][color=#007700]++){            for([/color][color=#0000bb]int l[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]l[/color][color=#007700]<[/color][color=#0000bb]n[/color][color=#007700];[/color][color=#0000bb]l[/color][color=#007700]++){                [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"  "[/color][color=#007700]+[/color][color=#0000bb]mta[/color][color=#007700][[/color][color=#0000bb]k[/color][color=#007700]][[/color][color=#0000bb]l[/color][color=#007700]]+[/color][color=#dd0000]""[/color][color=#007700]);            }            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]();        }    }    public static [/color][color=#0000bb]void matranb[/color][color=#007700]([/color][color=#0000bb]int m[/color][color=#007700],[/color][color=#0000bb]int n[/color][color=#007700]){        [/color][color=#0000bb]scanner input[/color][color=#007700]=new [/color][color=#0000bb]scanner[/color][color=#007700]([/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]in[/color][color=#007700]);        [/color][color=#0000bb]int [/color][color=#007700][][][/color][color=#0000bb]mtb[/color][color=#007700]=new [/color][color=#0000bb]int[/color][color=#007700][[/color][color=#0000bb]m[/color][color=#007700]][[/color][color=#0000bb]n[/color][color=#007700]];        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"+cac phan tu cua ma tran b:"[/color][color=#007700]);        for([/color][color=#0000bb]int i[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]<[/color][color=#0000bb]m[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]++){            for([/color][color=#0000bb]int j[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]j[/color][color=#007700]<[/color][color=#0000bb]n[/color][color=#007700];[/color][color=#0000bb]j[/color][color=#007700]++){                [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"a("[/color][color=#007700]+[/color][color=#0000bb]i[/color][color=#007700]+[/color][color=#dd0000]","[/color][color=#007700]+[/color][color=#0000bb]j[/color][color=#007700]+[/color][color=#dd0000]")="[/color][color=#007700]);                [/color][color=#0000bb]mtb[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]][[/color][color=#0000bb]j[/color][color=#007700]]=[/color][color=#0000bb]nhap[/color][color=#007700]();            }        }        for([/color][color=#0000bb]int k[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]k[/color][color=#007700]<[/color][color=#0000bb]m[/color][color=#007700];[/color][color=#0000bb]k[/color][color=#007700]++){            for([/color][color=#0000bb]int l[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]l[/color][color=#007700]<[/color][color=#0000bb]n[/color][color=#007700];[/color][color=#0000bb]l[/color][color=#007700]++){                [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"  "[/color][color=#007700]+[/color][color=#0000bb]mtb[/color][color=#007700][[/color][color=#0000bb]k[/color][color=#007700]][[/color][color=#0000bb]l[/color][color=#007700]]+[/color][color=#dd0000]""[/color][color=#007700]);            }            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]();        }    }    public static [/color][color=#0000bb]void tonghaimatran[/color][color=#007700]([/color][color=#0000bb]int [/color][color=#007700][][][/color][color=#0000bb]mta[/color][color=#007700],[/color][color=#0000bb]int [/color][color=#007700][][][/color][color=#0000bb]mtb[/color][color=#007700],[/color][color=#0000bb]int [/color][color=#007700][][][/color][color=#0000bb]mtc[/color][color=#007700],[/color][color=#0000bb]int m[/color][color=#007700],[/color][color=#0000bb]int n[/color][color=#007700]){               [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"+tong cua hai ma tran:"[/color][color=#007700]);        for([/color][color=#0000bb]int i[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]<[/color][color=#0000bb]m[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]++){            for([/color][color=#0000bb]int j[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]j[/color][color=#007700]<[/color][color=#0000bb]n[/color][color=#007700];[/color][color=#0000bb]j[/color][color=#007700]++){                [/color][color=#0000bb]mtc[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]][[/color][color=#0000bb]j[/color][color=#007700]]=[/color][color=#0000bb]mta[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]][[/color][color=#0000bb]j[/color][color=#007700]]+[/color][color=#0000bb]mtb[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]][[/color][color=#0000bb]j[/color][color=#007700]];                [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"  "[/color][color=#007700]+[/color][color=#0000bb]mtc[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]][[/color][color=#0000bb]j[/color][color=#007700]]+[/color][color=#dd0000]"\t"[/color][color=#007700]);            }            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]();        }    }    public static [/color][color=#0000bb]void main[/color][color=#007700]([/color][color=#0000bb]string[/color][color=#007700][][/color][color=#0000bb]args[/color][color=#007700]){        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"+kich co cua hai ma tran:"[/color][color=#007700]);        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"      +so hang:"[/color][color=#007700]);        [/color][color=#0000bb]int m[/color][color=#007700]=[/color][color=#0000bb]nhap[/color][color=#007700]();        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"      +so cot:"[/color][color=#007700]);        [/color][color=#0000bb]int n[/color][color=#007700]=[/color][color=#0000bb]nhap[/color][color=#007700]();        [/color][color=#0000bb]matrana[/color][color=#007700]([/color][color=#0000bb]m[/color][color=#007700],[/color][color=#0000bb]n[/color][color=#007700]);        [/color][color=#0000bb]matranb[/color][color=#007700]([/color][color=#0000bb]m[/color][color=#007700],[/color][color=#0000bb]n[/color][color=#007700]);        [/color][color=#0000bb]tonghaimatran[/color][color=#007700]([/color][color=#0000bb]mta[/color][color=#007700],[/color][color=#0000bb]mtb[/color][color=#007700],[/color][color=#0000bb]mtc[/color][color=#007700],[/color][color=#0000bb]m[/color][color=#007700],[/color][color=#0000bb]n[/color][color=#007700]);    }}[/color] 

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[duongnguyen]

bai 2:
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[color=#000000]
package javabasic[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]util[/color][color=#007700].[/color][color=#0000bb]scanner[/color][color=#007700];public class [/color][color=#0000bb]sapxepmang [/color][color=#007700]{    public static [/color][color=#0000bb]int nhap[/color][color=#007700](){        [/color][color=#0000bb]scanner input[/color][color=#007700]=new [/color][color=#0000bb]scanner[/color][color=#007700]([/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]in[/color][color=#007700]);        [/color][color=#0000bb]boolean bl[/color][color=#007700]=[/color][color=#0000bb]false[/color][color=#007700];        [/color][color=#0000bb]int n[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];        while(![/color][color=#0000bb]bl[/color][color=#007700]){            try{                [/color][color=#0000bb]n[/color][color=#007700]=[/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextint[/color][color=#007700]();                [/color][color=#0000bb]bl[/color][color=#007700]=[/color][color=#0000bb]true[/color][color=#007700];            }            catch([/color][color=#0000bb]exception e[/color][color=#007700]){                [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"moi ban nhap so:"[/color][color=#007700]);                [/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();            }        }        return([/color][color=#0000bb]n[/color][color=#007700]);    }    public static [/color][color=#0000bb]void main[/color][color=#007700]([/color][color=#0000bb]string[/color][color=#007700][][/color][color=#0000bb]args[/color][color=#007700]){        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"ban muon nhap mot day co bao nhieu so?"[/color][color=#007700]);        [/color][color=#0000bb]int s[/color][color=#007700]=[/color][color=#0000bb]nhap[/color][color=#007700]();        [/color][color=#0000bb]int [/color][color=#007700][][/color][color=#0000bb]dayso[/color][color=#007700]=new [/color][color=#0000bb]int[/color][color=#007700][[/color][color=#0000bb]s[/color][color=#007700]];        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"moi ban nhap cac so nguyen cua day:"[/color][color=#007700]);        for([/color][color=#0000bb]int i[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]<[/color][color=#0000bb]s[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]++){            [/color][color=#0000bb]dayso[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]]=[/color][color=#0000bb]nhap[/color][color=#007700]();        }        for([/color][color=#0000bb]int j[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]j[/color][color=#007700]<[/color][color=#0000bb]s[/color][color=#007700];[/color][color=#0000bb]j[/color][color=#007700]++){            for([/color][color=#0000bb]int k[/color][color=#007700]=[/color][color=#0000bb]j[/color][color=#007700]+[/color][color=#0000bb]1[/color][color=#007700];[/color][color=#0000bb]k[/color][color=#007700]<=[/color][color=#0000bb]s[/color][color=#007700]-[/color][color=#0000bb]1[/color][color=#007700];[/color][color=#0000bb]k[/color][color=#007700]++){                if([/color][color=#0000bb]dayso[/color][color=#007700][[/color][color=#0000bb]k[/color][color=#007700]]<=[/color][color=#0000bb]dayso[/color][color=#007700][[/color][color=#0000bb]j[/color][color=#007700]]){                    [/color][color=#0000bb]int hv[/color][color=#007700]=[/color][color=#0000bb]dayso[/color][color=#007700][[/color][color=#0000bb]k[/color][color=#007700]];                    [/color][color=#0000bb]dayso[/color][color=#007700][[/color][color=#0000bb]k[/color][color=#007700]]=[/color][color=#0000bb]dayso[/color][color=#007700][[/color][color=#0000bb]j[/color][color=#007700]];                    [/color][color=#0000bb]dayso[/color][color=#007700][[/color][color=#0000bb]j[/color][color=#007700]]=[/color][color=#0000bb]hv[/color][color=#007700];                }            }        }        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"thu tu tang dan cua day:"[/color][color=#007700]);        for([/color][color=#0000bb]int l[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]l[/color][color=#007700]<[/color][color=#0000bb]s[/color][color=#007700];[/color][color=#0000bb]l[/color][color=#007700]++)            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#0000bb]dayso[/color][color=#007700][[/color][color=#0000bb]l[/color][color=#007700]]+[/color][color=#dd0000]","[/color][color=#007700]);    }}[/color] 

</blockquote></div>
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[bacsichuabenh]

bai 3:
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[color=#000000]
package javabasic[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]util[/color][color=#007700].[/color][color=#0000bb]scanner[/color][color=#007700];public class [/color][color=#0000bb]manghaichieu[/color][color=#007700]{    public static [/color][color=#0000bb]int nhap[/color][color=#007700](){        [/color][color=#0000bb]scanner input[/color][color=#007700]=new [/color][color=#0000bb]scanner[/color][color=#007700]([/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]in[/color][color=#007700]);        [/color][color=#0000bb]boolean bl[/color][color=#007700]=[/color][color=#0000bb]false[/color][color=#007700];        [/color][color=#0000bb]int n[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];        while(![/color][color=#0000bb]bl[/color][color=#007700]){            try{                [/color][color=#0000bb]n[/color][color=#007700]=[/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextint[/color][color=#007700]();                [/color][color=#0000bb]bl[/color][color=#007700]=[/color][color=#0000bb]true[/color][color=#007700];            }            catch([/color][color=#0000bb]exception e[/color][color=#007700]){                [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"moi ban nhap lai:"[/color][color=#007700]);                [/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();            }        }        return([/color][color=#0000bb]n[/color][color=#007700]);    }    public static [/color][color=#0000bb]void main[/color][color=#007700]([/color][color=#0000bb]string[/color][color=#007700][][/color][color=#0000bb]args[/color][color=#007700]){        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"+kich co cua hai ma tran:"[/color][color=#007700]);        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"      +so hang:"[/color][color=#007700]);        [/color][color=#0000bb]int m[/color][color=#007700]=[/color][color=#0000bb]nhap[/color][color=#007700]();        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"      +so cot:"[/color][color=#007700]);        [/color][color=#0000bb]int n[/color][color=#007700]=[/color][color=#0000bb]nhap[/color][color=#007700]();        [/color][color=#0000bb]int [/color][color=#007700][][][/color][color=#0000bb]mta[/color][color=#007700]=new [/color][color=#0000bb]int[/color][color=#007700][[/color][color=#0000bb]m[/color][color=#007700]][[/color][color=#0000bb]n[/color][color=#007700]];        [/color][color=#0000bb]int [/color][color=#007700][][][/color][color=#0000bb]mtc[/color][color=#007700]=new [/color][color=#0000bb]int[/color][color=#007700][[/color][color=#0000bb]m[/color][color=#007700]][[/color][color=#0000bb]n[/color][color=#007700]];        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"+cac phan tu cua ma tran a:"[/color][color=#007700]);        for([/color][color=#0000bb]int i[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]<[/color][color=#0000bb]m[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]++){            for([/color][color=#0000bb]int j[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]j[/color][color=#007700]<[/color][color=#0000bb]n[/color][color=#007700];[/color][color=#0000bb]j[/color][color=#007700]++){                [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"a("[/color][color=#007700]+[/color][color=#0000bb]i[/color][color=#007700]+[/color][color=#dd0000]","[/color][color=#007700]+[/color][color=#0000bb]j[/color][color=#007700]+[/color][color=#dd0000]")="[/color][color=#007700]);                [/color][color=#0000bb]mta[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]][[/color][color=#0000bb]j[/color][color=#007700]]=[/color][color=#0000bb]nhap[/color][color=#007700]();            }        }        for([/color][color=#0000bb]int k[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]k[/color][color=#007700]<[/color][color=#0000bb]m[/color][color=#007700];[/color][color=#0000bb]k[/color][color=#007700]++){            for([/color][color=#0000bb]int l[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]l[/color][color=#007700]<[/color][color=#0000bb]n[/color][color=#007700];[/color][color=#0000bb]l[/color][color=#007700]++){                [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"    "[/color][color=#007700]+[/color][color=#0000bb]mta[/color][color=#007700][[/color][color=#0000bb]k[/color][color=#007700]][[/color][color=#0000bb]l[/color][color=#007700]]+[/color][color=#dd0000]""[/color][color=#007700]);            }            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]();        }        [/color][color=#0000bb]int [/color][color=#007700][][][/color][color=#0000bb]mtb[/color][color=#007700]=new [/color][color=#0000bb]int[/color][color=#007700][[/color][color=#0000bb]m[/color][color=#007700]][[/color][color=#0000bb]n[/color][color=#007700]];        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"+cac phan tu cua ma tran b:"[/color][color=#007700]);        for([/color][color=#0000bb]int i[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]<[/color][color=#0000bb]m[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]++){            for([/color][color=#0000bb]int j[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]j[/color][color=#007700]<[/color][color=#0000bb]n[/color][color=#007700];[/color][color=#0000bb]j[/color][color=#007700]++){                [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"a("[/color][color=#007700]+[/color][color=#0000bb]i[/color][color=#007700]+[/color][color=#dd0000]","[/color][color=#007700]+[/color][color=#0000bb]j[/color][color=#007700]+[/color][color=#dd0000]")="[/color][color=#007700]);                [/color][color=#0000bb]mtb[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]][[/color][color=#0000bb]j[/color][color=#007700]]=[/color][color=#0000bb]nhap[/color][color=#007700]();            }        }        for([/color][color=#0000bb]int k[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]k[/color][color=#007700]<[/color][color=#0000bb]m[/color][color=#007700];[/color][color=#0000bb]k[/color][color=#007700]++){            for([/color][color=#0000bb]int l[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]l[/color][color=#007700]<[/color][color=#0000bb]n[/color][color=#007700];[/color][color=#0000bb]l[/color][color=#007700]++){                [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"    "[/color][color=#007700]+[/color][color=#0000bb]mtb[/color][color=#007700][[/color][color=#0000bb]k[/color][color=#007700]][[/color][color=#0000bb]l[/color][color=#007700]]+[/color][color=#dd0000]""[/color][color=#007700]);            }            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]();        }        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"+tong cua hai ma tran:"[/color][color=#007700]);        for([/color][color=#0000bb]int i[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]<[/color][color=#0000bb]m[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]++){            for([/color][color=#0000bb]int j[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]j[/color][color=#007700]<[/color][color=#0000bb]n[/color][color=#007700];[/color][color=#0000bb]j[/color][color=#007700]++){                [/color][color=#0000bb]mtc[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]][[/color][color=#0000bb]j[/color][color=#007700]]=[/color][color=#0000bb]mta[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]][[/color][color=#0000bb]j[/color][color=#007700]]+[/color][color=#0000bb]mtb[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]][[/color][color=#0000bb]j[/color][color=#007700]];                [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"    "[/color][color=#007700]+[/color][color=#0000bb]mtc[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]][[/color][color=#0000bb]j[/color][color=#007700]]);            }            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]();        }    }}[/color] 

</blockquote></div>
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[vongocbao]

bắt đầu từ bài này ad cho bài tập căng quá, e chả biết làm sao cả

[yeubongda1102]

[color=#000000]
import java[/color][color=#007700].[/color][color=#0000bb]util[/color][color=#007700].[/color][color=#0000bb]scanner[/color][color=#007700];[/color][color=#ff8000]/**** @author thanh*/[/color][color=#007700]public class [/color][color=#0000bb]cau1 [/color][color=#007700]{    public static [/color][color=#0000bb]void main [/color][color=#007700]([/color][color=#0000bb]string [/color][color=#007700][] [/color][color=#0000bb]args[/color][color=#007700]){        [/color][color=#0000bb]int a[/color][color=#007700], [/color][color=#0000bb]i[/color][color=#007700];        [/color][color=#0000bb]scanner duc [/color][color=#007700]= new [/color][color=#0000bb]scanner[/color][color=#007700]([/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]in[/color][color=#007700]);        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"số sinh viên: "[/color][color=#007700]);        [/color][color=#0000bb]a [/color][color=#007700]= [/color][color=#0000bb]duc[/color][color=#007700].[/color][color=#0000bb]nextint[/color][color=#007700]();        [/color][color=#0000bb]duc[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();        [/color][color=#0000bb]string arr[/color][color=#007700][] = new [/color][color=#0000bb]string[/color][color=#007700][[/color][color=#0000bb]a[/color][color=#007700]];    if([/color][color=#0000bb]a[/color][color=#007700]>[/color][color=#0000bb]0[/color][color=#007700]){            for([/color][color=#0000bb]i[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]<[/color][color=#0000bb]a[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]++){                [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"nhập tên sinh viên thứ "[/color][color=#007700]+([/color][color=#0000bb]i[/color][color=#007700]+[/color][color=#0000bb]1[/color][color=#007700])+[/color][color=#dd0000]" : "[/color][color=#007700]);                [/color][color=#0000bb]arr[/color][color=#007700][[/color][color=#0000bb]a[/color][color=#007700]]=[/color][color=#0000bb]duc[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();            }            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"nhập tên sinh viên cần tìm: "[/color][color=#007700]);            [/color][color=#0000bb]string ten [/color][color=#007700]= [/color][color=#0000bb]duc[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();            [/color][color=#0000bb]int x[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];            for([/color][color=#0000bb]i[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]<[/color][color=#0000bb]a[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]++)            {                if([/color][color=#0000bb]ten[/color][color=#007700].[/color][color=#0000bb]equals[/color][color=#007700]([/color][color=#0000bb]arr[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]]))                  [/color][color=#0000bb]x[/color][color=#007700]=[/color][color=#0000bb]x[/color][color=#007700]+[/color][color=#0000bb]1[/color][color=#007700];            }        if([/color][color=#0000bb]x[/color][color=#007700]>[/color][color=#0000bb]0[/color][color=#007700])          [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"tên "[/color][color=#007700]+[/color][color=#0000bb]ten[/color][color=#007700]+[/color][color=#dd0000]"  có trong danh sách"[/color][color=#007700]);        else          [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"tên "[/color][color=#007700]+[/color][color=#0000bb]ten[/color][color=#007700]+[/color][color=#dd0000]" không có trong danh sách"[/color][color=#007700]);        }        else{            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"nhập số sinh viên lớn hơn 0"[/color][color=#007700]);        }    }}[/color] 

[robocomputer]

bài 1:
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[color=#000000]
package baitap[/color][color=#007700]; [/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]util[/color][color=#007700].[/color][color=#0000bb]scanner[/color][color=#007700]; public class [/color][color=#0000bb]bai1 [/color][color=#007700]{     public static [/color][color=#0000bb]void main[/color][color=#007700]([/color][color=#0000bb]string[/color][color=#007700][] [/color][color=#0000bb]args[/color][color=#007700]) {        [/color][color=#0000bb]int a[/color][color=#007700], [/color][color=#0000bb]i[/color][color=#007700];        [/color][color=#0000bb]scanner nhapdulieu [/color][color=#007700]= new [/color][color=#0000bb]scanner[/color][color=#007700]([/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]in[/color][color=#007700]);        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"so sinh vien: "[/color][color=#007700]);        [/color][color=#0000bb]a [/color][color=#007700]= [/color][color=#0000bb]nhapdulieu[/color][color=#007700].[/color][color=#0000bb]nextint[/color][color=#007700]();        [/color][color=#0000bb]nhapdulieu[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();        [/color][color=#0000bb]string arrstring[/color][color=#007700][] = new [/color][color=#0000bb]string[/color][color=#007700][[/color][color=#0000bb]a[/color][color=#007700]];         if ([/color][color=#0000bb]a [/color][color=#007700]> [/color][color=#0000bb]0[/color][color=#007700]) {            for ([/color][color=#0000bb]i [/color][color=#007700]= [/color][color=#0000bb]0[/color][color=#007700]; [/color][color=#0000bb]i [/color][color=#007700]< [/color][color=#0000bb]a[/color][color=#007700]; [/color][color=#0000bb]i[/color][color=#007700]++) {                [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"nhap ten sinh vien thu " [/color][color=#007700]+[/color][color=#0000bb]i[/color][color=#007700]);                [/color][color=#0000bb]arrstring[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]] = [/color][color=#0000bb]nhapdulieu[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();            }            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"nhap ten sinh vien can tim "[/color][color=#007700]);            [/color][color=#0000bb]string ten [/color][color=#007700]= [/color][color=#0000bb]nhapdulieu[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();            [/color][color=#0000bb]int x[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];            for([/color][color=#0000bb]i[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]<[/color][color=#0000bb]a[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]++)            {                if([/color][color=#0000bb]ten[/color][color=#007700].[/color][color=#0000bb]equals[/color][color=#007700]([/color][color=#0000bb]arrstring[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]]))                  [/color][color=#0000bb]x[/color][color=#007700]=[/color][color=#0000bb]x[/color][color=#007700]+[/color][color=#0000bb]1[/color][color=#007700];            }        if([/color][color=#0000bb]x[/color][color=#007700]>[/color][color=#0000bb]0[/color][color=#007700])          [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"ten "[/color][color=#007700]+[/color][color=#0000bb]ten[/color][color=#007700]+[/color][color=#dd0000]"  co trong danh sach"[/color][color=#007700]);        else          [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"ten "[/color][color=#007700]+[/color][color=#0000bb]ten[/color][color=#007700]+[/color][color=#dd0000]" khong co trong danh sach"[/color][color=#007700]);        }        else{            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"nhap so sinh vien lon hon 0"[/color][color=#007700]);        }       }}[/color] 

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bài 2:
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[color=#000000]
package baitap[/color][color=#007700]; [/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]util[/color][color=#007700].[/color][color=#0000bb]scanner[/color][color=#007700]; public class [/color][color=#0000bb]bai2 [/color][color=#007700]{     public static [/color][color=#0000bb]void main[/color][color=#007700]([/color][color=#0000bb]string[/color][color=#007700][] [/color][color=#0000bb]args[/color][color=#007700]) {        [/color][color=#0000bb]int n[/color][color=#007700], [/color][color=#0000bb]k[/color][color=#007700];        [/color][color=#0000bb]scanner nhapdulieu [/color][color=#007700]= new [/color][color=#0000bb]scanner[/color][color=#007700]([/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]in[/color][color=#007700]);        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"nhap so phan tu can nhap "[/color][color=#007700]);        [/color][color=#0000bb]n [/color][color=#007700]= [/color][color=#0000bb]nhapdulieu[/color][color=#007700].[/color][color=#0000bb]nextint[/color][color=#007700]();        [/color][color=#0000bb]int arrint[/color][color=#007700][] = new [/color][color=#0000bb]int[/color][color=#007700][[/color][color=#0000bb]n[/color][color=#007700]];        if([/color][color=#0000bb]n[/color][color=#007700]>[/color][color=#0000bb]0[/color][color=#007700])        {        for ([/color][color=#0000bb]int i [/color][color=#007700]= [/color][color=#0000bb]0[/color][color=#007700]; [/color][color=#0000bb]i [/color][color=#007700]< [/color][color=#0000bb]n[/color][color=#007700]; [/color][color=#0000bb]i[/color][color=#007700]++) {            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"nhap phan tu thu " [/color][color=#007700]+[/color][color=#0000bb]i[/color][color=#007700]);            [/color][color=#0000bb]arrint[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]] = [/color][color=#0000bb]nhapdulieu[/color][color=#007700].[/color][color=#0000bb]nextint[/color][color=#007700]();        }        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"day so vua nhap la " [/color][color=#007700]);        for ([/color][color=#0000bb]int i [/color][color=#007700]= [/color][color=#0000bb]0[/color][color=#007700]; [/color][color=#0000bb]i [/color][color=#007700]< [/color][color=#0000bb]n[/color][color=#007700]; [/color][color=#0000bb]i[/color][color=#007700]++) {            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#0000bb]arrint[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]]+ [/color][color=#dd0000]" "[/color][color=#007700]);        }        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]();        for ([/color][color=#0000bb]int i [/color][color=#007700]= [/color][color=#0000bb]0[/color][color=#007700]; [/color][color=#0000bb]i [/color][color=#007700]< [/color][color=#0000bb]n [/color][color=#007700]- [/color][color=#0000bb]1[/color][color=#007700]; [/color][color=#0000bb]i[/color][color=#007700]++) {            for ([/color][color=#0000bb]int j [/color][color=#007700]= [/color][color=#0000bb]i [/color][color=#007700]+ [/color][color=#0000bb]1[/color][color=#007700]; [/color][color=#0000bb]j [/color][color=#007700]< [/color][color=#0000bb]n[/color][color=#007700]; [/color][color=#0000bb]j[/color][color=#007700]++) {                if ([/color][color=#0000bb]arrint[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]] > [/color][color=#0000bb]arrint[/color][color=#007700][[/color][color=#0000bb]j[/color][color=#007700]]) {                    [/color][color=#0000bb]k [/color][color=#007700]= [/color][color=#0000bb]arrint[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]];                    [/color][color=#0000bb]arrint[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]] = [/color][color=#0000bb]arrint[/color][color=#007700][[/color][color=#0000bb]j[/color][color=#007700]];                    [/color][color=#0000bb]arrint[/color][color=#007700][[/color][color=#0000bb]j[/color][color=#007700]] = [/color][color=#0000bb]k[/color][color=#007700];                }            }        }        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"day so sau khi duoc sap xep la "[/color][color=#007700]);        for ([/color][color=#0000bb]int i [/color][color=#007700]= [/color][color=#0000bb]0[/color][color=#007700]; [/color][color=#0000bb]i [/color][color=#007700]< [/color][color=#0000bb]n[/color][color=#007700]; [/color][color=#0000bb]i[/color][color=#007700]++) {            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print( [/color][color=#0000bb]arrint[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]]+[/color][color=#dd0000]" "[/color][color=#007700]);        }        }        else            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"so phan tu nhap khong hop le"[/color][color=#007700]);    }}[/color] 

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bài 3:
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[color=#000000]
package baitap[/color][color=#007700]; [/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]util[/color][color=#007700].[/color][color=#0000bb]scanner[/color][color=#007700]; public class [/color][color=#0000bb]bai3 [/color][color=#007700]{     public static [/color][color=#0000bb]void main[/color][color=#007700]([/color][color=#0000bb]string[/color][color=#007700][] [/color][color=#0000bb]args[/color][color=#007700]) {        [/color][color=#0000bb]int[/color][color=#007700][][] [/color][color=#0000bb]arrint1[/color][color=#007700];        [/color][color=#0000bb]int[/color][color=#007700][][] [/color][color=#0000bb]arrint2[/color][color=#007700];        [/color][color=#0000bb]int n[/color][color=#007700], [/color][color=#0000bb]m[/color][color=#007700];        [/color][color=#0000bb]scanner nhapdulieu [/color][color=#007700]= new [/color][color=#0000bb]scanner[/color][color=#007700]([/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]in[/color][color=#007700]);        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"nhap so hang "[/color][color=#007700]);        [/color][color=#0000bb]n [/color][color=#007700]= [/color][color=#0000bb]nhapdulieu[/color][color=#007700].[/color][color=#0000bb]nextint[/color][color=#007700]();        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"nhap so cot "[/color][color=#007700]);        [/color][color=#0000bb]m [/color][color=#007700]= [/color][color=#0000bb]nhapdulieu[/color][color=#007700].[/color][color=#0000bb]nextint[/color][color=#007700]();        [/color][color=#0000bb]arrint1 [/color][color=#007700]= new [/color][color=#0000bb]int[/color][color=#007700][[/color][color=#0000bb]n[/color][color=#007700]][[/color][color=#0000bb]m[/color][color=#007700]];        [/color][color=#0000bb]arrint2 [/color][color=#007700]= new [/color][color=#0000bb]int[/color][color=#007700][[/color][color=#0000bb]n[/color][color=#007700]][[/color][color=#0000bb]m[/color][color=#007700]];        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"nhap ma tran 1"[/color][color=#007700]);        for ([/color][color=#0000bb]int i [/color][color=#007700]= [/color][color=#0000bb]0[/color][color=#007700]; [/color][color=#0000bb]i [/color][color=#007700]< [/color][color=#0000bb]n[/color][color=#007700]; [/color][color=#0000bb]i[/color][color=#007700]++) {            for ([/color][color=#0000bb]int j [/color][color=#007700]= [/color][color=#0000bb]0[/color][color=#007700]; [/color][color=#0000bb]j [/color][color=#007700]< [/color][color=#0000bb]m[/color][color=#007700]; [/color][color=#0000bb]j[/color][color=#007700]++) {                [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"nhap phan tu hang " [/color][color=#007700]+ [/color][color=#0000bb]i [/color][color=#007700]+ [/color][color=#dd0000]" cot " [/color][color=#007700]+ [/color][color=#0000bb]j[/color][color=#007700]+[/color][color=#dd0000]" "[/color][color=#007700]);                [/color][color=#0000bb]arrint1[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]][[/color][color=#0000bb]j[/color][color=#007700]] = [/color][color=#0000bb]nhapdulieu[/color][color=#007700].[/color][color=#0000bb]nextint[/color][color=#007700]();            }        }        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"nhap ma tran 2"[/color][color=#007700]);        for ([/color][color=#0000bb]int i [/color][color=#007700]= [/color][color=#0000bb]0[/color][color=#007700]; [/color][color=#0000bb]i [/color][color=#007700]< [/color][color=#0000bb]n[/color][color=#007700]; [/color][color=#0000bb]i[/color][color=#007700]++) {            for ([/color][color=#0000bb]int j [/color][color=#007700]= [/color][color=#0000bb]0[/color][color=#007700]; [/color][color=#0000bb]j [/color][color=#007700]< [/color][color=#0000bb]m[/color][color=#007700]; [/color][color=#0000bb]j[/color][color=#007700]++) {                [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"nhap phan tu hang " [/color][color=#007700]+ [/color][color=#0000bb]i [/color][color=#007700]+ [/color][color=#dd0000]" cot " [/color][color=#007700]+ [/color][color=#0000bb]j[/color][color=#007700]+[/color][color=#dd0000]" "[/color][color=#007700]);                [/color][color=#0000bb]arrint2[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]][[/color][color=#0000bb]j[/color][color=#007700]] = [/color][color=#0000bb]nhapdulieu[/color][color=#007700].[/color][color=#0000bb]nextint[/color][color=#007700]();            }        }        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"ma tran 1 vua nhap "[/color][color=#007700]);        for ([/color][color=#0000bb]int i [/color][color=#007700]= [/color][color=#0000bb]0[/color][color=#007700]; [/color][color=#0000bb]i [/color][color=#007700]< [/color][color=#0000bb]n[/color][color=#007700]; [/color][color=#0000bb]i[/color][color=#007700]++) {            for ([/color][color=#0000bb]int j [/color][color=#007700]= [/color][color=#0000bb]0[/color][color=#007700]; [/color][color=#0000bb]j [/color][color=#007700]< [/color][color=#0000bb]m[/color][color=#007700]; [/color][color=#0000bb]j[/color][color=#007700]++) {                [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#0000bb]arrint1[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]][[/color][color=#0000bb]j[/color][color=#007700]]+[/color][color=#dd0000]" "[/color][color=#007700]);            }            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]();        }        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"ma tran 2 vua nhap "[/color][color=#007700]);        for ([/color][color=#0000bb]int i [/color][color=#007700]= [/color][color=#0000bb]0[/color][color=#007700]; [/color][color=#0000bb]i [/color][color=#007700]< [/color][color=#0000bb]n[/color][color=#007700]; [/color][color=#0000bb]i[/color][color=#007700]++) {            for ([/color][color=#0000bb]int j [/color][color=#007700]= [/color][color=#0000bb]0[/color][color=#007700]; [/color][color=#0000bb]j [/color][color=#007700]< [/color][color=#0000bb]m[/color][color=#007700]; [/color][color=#0000bb]j[/color][color=#007700]++) {                [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#0000bb]arrint2[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]][[/color][color=#0000bb]j[/color][color=#007700]]+[/color][color=#dd0000]" "[/color][color=#007700]);            }            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]();        }        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"tong 2 ma tran vua nhap la "[/color][color=#007700]);        for([/color][color=#0000bb]int i[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]<[/color][color=#0000bb]n[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]++)        {            for([/color][color=#0000bb]int j[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]j[/color][color=#007700]<[/color][color=#0000bb]m[/color][color=#007700];[/color][color=#0000bb]j[/color][color=#007700]++)            {              [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#0000bb]arrint1[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]][[/color][color=#0000bb]j[/color][color=#007700]]+[/color][color=#0000bb]arrint2[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]][[/color][color=#0000bb]j[/color][color=#007700]]+[/color][color=#dd0000]" "[/color][color=#007700]);            }            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]();        }    }}[/color] 

</blockquote></div>
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bạn cho mình hỏi, ở bài 1 có dòng lệnh

[color=#000000]
  nhapdulieu[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();        [/color][color=#0000bb]string arrstring[/color][color=#007700][] = new [/color][color=#0000bb]string[/color][color=#007700][[/color][color=#0000bb]a[/color][color=#007700]];[/color] 

cái dòng lệnh này nếu mình bỏ đi thì chương trình ko báo lỗi và chạy vẫn được, nhưng khi nhập giá trị trong console thì nó xuất hiện cái lỗi là không cho nhập phần tử thứ 0, nó sẽ chỉ cho nhập kể từ phần tử thứ 1
bạn có thể giải thích cho mình vs đc ko

[hocnauan]

bài 1:
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[color=#000000]
package javacoban[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]util[/color][color=#007700].[/color][color=#0000bb]scanner[/color][color=#007700];[/color][color=#ff8000]/**** @author admin*/[/color][color=#007700]public class [/color][color=#0000bb]bai9_1 [/color][color=#007700]{    public static [/color][color=#0000bb]void main[/color][color=#007700]([/color][color=#0000bb]string[/color][color=#007700][] [/color][color=#0000bb]args[/color][color=#007700]) {        [/color][color=#0000bb]int sinhvien[/color][color=#007700], [/color][color=#0000bb]i[/color][color=#007700];        [/color][color=#0000bb]string tim[/color][color=#007700];        [/color][color=#0000bb]boolean kq [/color][color=#007700]= [/color][color=#0000bb]false[/color][color=#007700];        [/color][color=#0000bb]scanner nhapdulieu [/color][color=#007700]= new [/color][color=#0000bb]scanner[/color][color=#007700]([/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]in[/color][color=#007700]);        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"nhập số sinh viên: "[/color][color=#007700]);        [/color][color=#0000bb]sinhvien [/color][color=#007700]= [/color][color=#0000bb]nhapdulieu[/color][color=#007700].[/color][color=#0000bb]nextint[/color][color=#007700]();        [/color][color=#0000bb]nhapdulieu[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();        [/color][color=#0000bb]string hoten[/color][color=#007700][] = new [/color][color=#0000bb]string[/color][color=#007700][[/color][color=#0000bb]sinhvien[/color][color=#007700]];[/color][color=#ff8000]//khai báo mảng và cấp phát bộ nhớ cho mảng        [/color][color=#007700]for([/color][color=#0000bb]i [/color][color=#007700]= [/color][color=#0000bb]0[/color][color=#007700]; [/color][color=#0000bb]i [/color][color=#007700]< [/color][color=#0000bb]sinhvien[/color][color=#007700]; [/color][color=#0000bb]i[/color][color=#007700]++) {            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"nhập họ tên sinh viên " [/color][color=#007700]+ [/color][color=#0000bb]i [/color][color=#007700]+ [/color][color=#dd0000]": "[/color][color=#007700]);            [/color][color=#0000bb]hoten[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]] = [/color][color=#0000bb]nhapdulieu[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();        }        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"nhập tên sinh viên muốn tìm: "[/color][color=#007700]);        [/color][color=#0000bb]tim [/color][color=#007700]= [/color][color=#0000bb]nhapdulieu[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();        for([/color][color=#0000bb]i [/color][color=#007700]= [/color][color=#0000bb]0[/color][color=#007700]; [/color][color=#0000bb]i [/color][color=#007700]< [/color][color=#0000bb]sinhvien[/color][color=#007700]; [/color][color=#0000bb]i[/color][color=#007700]++) {            [/color][color=#0000bb]kq [/color][color=#007700]= [/color][color=#0000bb]tim[/color][color=#007700].[/color][color=#0000bb]equals[/color][color=#007700]([/color][color=#0000bb]hoten[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]]);        }        if([/color][color=#0000bb]kq [/color][color=#007700]== [/color][color=#0000bb]true[/color][color=#007700]) {            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"tìm thấy tên " [/color][color=#007700]+ [/color][color=#0000bb]tim[/color][color=#007700]);        }else {            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"không tìm thấy tên " [/color][color=#007700]+ [/color][color=#0000bb]tim[/color][color=#007700]);        }    }}[/color] 

</blockquote></div>
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bài 2:
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[color=#000000]
package javacoban[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]util[/color][color=#007700].[/color][color=#0000bb]scanner[/color][color=#007700];[/color][color=#ff8000]/**** @author admin*/[/color][color=#007700]public class [/color][color=#0000bb]newclass [/color][color=#007700]{    public static [/color][color=#0000bb]void main[/color][color=#007700]([/color][color=#0000bb]string[/color][color=#007700][] [/color][color=#0000bb]args[/color][color=#007700]) {        [/color][color=#0000bb]int a[/color][color=#007700], [/color][color=#0000bb]i[/color][color=#007700], [/color][color=#0000bb]j[/color][color=#007700], [/color][color=#0000bb]temp[/color][color=#007700];        [/color][color=#0000bb]scanner nhapdulieu [/color][color=#007700]= new [/color][color=#0000bb]scanner[/color][color=#007700]([/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]in[/color][color=#007700]);        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"nhập số phần tử của mảng: "[/color][color=#007700]);        [/color][color=#0000bb]a [/color][color=#007700]= [/color][color=#0000bb]nhapdulieu[/color][color=#007700].[/color][color=#0000bb]nextint[/color][color=#007700]();        [/color][color=#0000bb]int b[/color][color=#007700][]; [/color][color=#ff8000]//khai báo mảng b        [/color][color=#0000bb]b [/color][color=#007700]= new [/color][color=#0000bb]int[/color][color=#007700][[/color][color=#0000bb]a[/color][color=#007700]]; [/color][color=#ff8000]//cấp phát mảng b có a phần tử        [/color][color=#007700]for([/color][color=#0000bb]i [/color][color=#007700]= [/color][color=#0000bb]0[/color][color=#007700]; [/color][color=#0000bb]i [/color][color=#007700]< [/color][color=#0000bb]a[/color][color=#007700]; [/color][color=#0000bb]i[/color][color=#007700]++) {            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"nhập số n thứ " [/color][color=#007700]+ [/color][color=#0000bb]i[/color][color=#007700]);            [/color][color=#0000bb]b[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]] = [/color][color=#0000bb]nhapdulieu[/color][color=#007700].[/color][color=#0000bb]nextint[/color][color=#007700]();        }        for([/color][color=#0000bb]i [/color][color=#007700]= [/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]i [/color][color=#007700]< [/color][color=#0000bb]a[/color][color=#007700]; [/color][color=#0000bb]i[/color][color=#007700]++){            for([/color][color=#0000bb]j [/color][color=#007700]= [/color][color=#0000bb]0[/color][color=#007700]; [/color][color=#0000bb]j [/color][color=#007700]<= [/color][color=#0000bb]i [/color][color=#007700]; [/color][color=#0000bb]j[/color][color=#007700]++){                if([/color][color=#0000bb]b[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]]<[/color][color=#0000bb]b[/color][color=#007700][[/color][color=#0000bb]j[/color][color=#007700]]){                    [/color][color=#0000bb]temp [/color][color=#007700]= [/color][color=#0000bb]b[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]];                    [/color][color=#0000bb]b[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]] = [/color][color=#0000bb]b[/color][color=#007700][[/color][color=#0000bb]j[/color][color=#007700]];                    [/color][color=#0000bb]b[/color][color=#007700][[/color][color=#0000bb]j[/color][color=#007700]]= [/color][color=#0000bb]temp[/color][color=#007700];                }            }        }        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"mảng sắp xếp lại: "[/color][color=#007700]);        for([/color][color=#0000bb]i [/color][color=#007700]= [/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]i [/color][color=#007700]< [/color][color=#0000bb]a[/color][color=#007700]; [/color][color=#0000bb]i[/color][color=#007700]++){            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#0000bb]b[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]]+[/color][color=#dd0000]" "[/color][color=#007700]);        }    }}[/color] 

</blockquote></div>
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[baby.panda6789]

mình nộp bài:
câu 1:
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[color=#000000]
package [/color][color=#007700]array; [/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].*;[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]util[/color][color=#007700].[/color][color=#0000bb]scanner[/color][color=#007700]; public class [/color][color=#0000bb]bai1 [/color][color=#007700]{    public static [/color][color=#0000bb]void main[/color][color=#007700]([/color][color=#0000bb]string [/color][color=#007700][] [/color][color=#0000bb]args[/color][color=#007700]){        [/color][color=#0000bb]scanner input [/color][color=#007700]= new [/color][color=#0000bb]scanner[/color][color=#007700]([/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]in[/color][color=#007700]);        [/color][color=#0000bb]sinhvienlist sinhvien[/color][color=#007700];        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"nhap so sinh vien: "[/color][color=#007700]);        [/color][color=#0000bb]int n [/color][color=#007700]= [/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextint[/color][color=#007700]();        [/color][color=#0000bb]sinhvien [/color][color=#007700]= new [/color][color=#0000bb]sinhvienlist[/color][color=#007700]([/color][color=#0000bb]n[/color][color=#007700]);        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"sinh vien vua nhap la: "[/color][color=#007700]);        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#0000bb]sinhvien[/color][color=#007700]);        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"nhap sinh vien can tim kiem: "[/color][color=#007700]);        [/color][color=#0000bb]string nextline [/color][color=#007700]= [/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();        [/color][color=#0000bb]string name [/color][color=#007700]= [/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();        [/color][color=#0000bb]int i [/color][color=#007700]= [/color][color=#0000bb]sinhvien[/color][color=#007700].[/color][color=#0000bb]timkiem[/color][color=#007700]([/color][color=#0000bb]name[/color][color=#007700]);        if([/color][color=#0000bb]i[/color][color=#007700]!= -[/color][color=#0000bb]1[/color][color=#007700]){            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"sinh vien tim thay la: "[/color][color=#007700]+[/color][color=#0000bb]sinhvien[/color][color=#007700].[/color][color=#0000bb]getsinhvien[/color][color=#007700]([/color][color=#0000bb]i[/color][color=#007700]));        }else{            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"khong tim thay sinh vien nay"[/color][color=#007700]);        }    }}class [/color][color=#0000bb]sinhvien[/color][color=#007700]{    [/color][color=#0000bb]string hoten[/color][color=#007700];    public [/color][color=#0000bb]sinhvien[/color][color=#007700](){        [/color][color=#0000bb]this[/color][color=#007700].[/color][color=#0000bb]hoten [/color][color=#007700]= [/color][color=#dd0000]""[/color][color=#007700];    }    public [/color][color=#0000bb]string getname[/color][color=#007700](){        return [/color][color=#0000bb]hoten[/color][color=#007700];    }    public [/color][color=#0000bb]void nhap[/color][color=#007700](){        [/color][color=#0000bb]scanner input [/color][color=#007700]= new [/color][color=#0000bb]scanner[/color][color=#007700]([/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]in[/color][color=#007700]);        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"nhap ho ten: "[/color][color=#007700]);        [/color][color=#0000bb]hoten [/color][color=#007700]= [/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();    }    public [/color][color=#0000bb]string tostring[/color][color=#007700](){        return [/color][color=#dd0000]"ho ten: "[/color][color=#007700]+[/color][color=#0000bb]hoten[/color][color=#007700]+[/color][color=#dd0000]"
"[/color][color=#007700];    }}class [/color][color=#0000bb]sinhvienlist[/color][color=#007700]{    [/color][color=#0000bb]sinhvien[/color][color=#007700][] [/color][color=#0000bb]sv[/color][color=#007700];    public [/color][color=#0000bb]sinhvienlist[/color][color=#007700]([/color][color=#0000bb]int size[/color][color=#007700]){        [/color][color=#0000bb]sv [/color][color=#007700]= new [/color][color=#0000bb]sinhvien[/color][color=#007700][[/color][color=#0000bb]size[/color][color=#007700]];        for([/color][color=#0000bb]int i[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]<[/color][color=#0000bb]size[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]++){            [/color][color=#0000bb]sv[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]] = new [/color][color=#0000bb]sinhvien[/color][color=#007700]();            [/color][color=#0000bb]sv[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]].[/color][color=#0000bb]nhap[/color][color=#007700]();        }    }    public [/color][color=#0000bb]string tostring[/color][color=#007700](){        [/color][color=#0000bb]string s[/color][color=#007700]= [/color][color=#dd0000]""[/color][color=#007700];        for([/color][color=#0000bb]int i[/color][color=#007700]= [/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]<[/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]length[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]++){            [/color][color=#0000bb]s[/color][color=#007700]+=[/color][color=#0000bb]sv[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]];        }        return [/color][color=#0000bb]s[/color][color=#007700];    }    public [/color][color=#0000bb]sinhvien getsinhvien[/color][color=#007700]([/color][color=#0000bb]int i[/color][color=#007700]){        return [/color][color=#0000bb]sv[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]];    }    public [/color][color=#0000bb]int timkiem[/color][color=#007700]([/color][color=#0000bb]string name[/color][color=#007700]){        for([/color][color=#0000bb]int i[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]<[/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]length[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]++){            if([/color][color=#0000bb]sv[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]].[/color][color=#0000bb]getname[/color][color=#007700]().[/color][color=#0000bb]equalsignorecase[/color][color=#007700]([/color][color=#0000bb]name[/color][color=#007700])){                return [/color][color=#0000bb]i[/color][color=#007700];            }        }        return -[/color][color=#0000bb]1[/color][color=#007700];    }}[/color] 

</blockquote></div>
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</div>

câu 2:
<div class="bbcodeblock bbcodequote bbcmspoilerblock">
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[color=#000000]
package [/color][color=#007700]array; [/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]util[/color][color=#007700].*; public class [/color][color=#0000bb]bai2 [/color][color=#007700]{    public static [/color][color=#0000bb]void main[/color][color=#007700]([/color][color=#0000bb]string [/color][color=#007700][] [/color][color=#0000bb]args[/color][color=#007700]){        [/color][color=#0000bb]int n[/color][color=#007700];        [/color][color=#0000bb]int arrint[/color][color=#007700][];        [/color][color=#0000bb]scanner input [/color][color=#007700]= new [/color][color=#0000bb]scanner[/color][color=#007700]([/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]in[/color][color=#007700]);        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"nhap n: "[/color][color=#007700]);        [/color][color=#0000bb]n [/color][color=#007700]= [/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextint[/color][color=#007700]();        [/color][color=#0000bb]arrint [/color][color=#007700]= new [/color][color=#0000bb]int[/color][color=#007700][[/color][color=#0000bb]n[/color][color=#007700]];        for([/color][color=#0000bb]int i[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]<[/color][color=#0000bb]arrint[/color][color=#007700].[/color][color=#0000bb]length[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]++){            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"nhap gia tri thu "[/color][color=#007700]+([/color][color=#0000bb]i[/color][color=#007700]+[/color][color=#0000bb]1[/color][color=#007700])+[/color][color=#dd0000]": "[/color][color=#007700]);            [/color][color=#0000bb]arrint[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]] = [/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextint[/color][color=#007700]();        }        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"mang vua nhap la: "[/color][color=#007700]);        for([/color][color=#0000bb]int i[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]<[/color][color=#0000bb]arrint[/color][color=#007700].[/color][color=#0000bb]length[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]++){            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#0000bb]arrint[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]]+[/color][color=#dd0000]" "[/color][color=#007700]);        }        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]""[/color][color=#007700]);        [/color][color=#0000bb]int temp[/color][color=#007700];        for([/color][color=#0000bb]int i[/color][color=#007700]=[/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]<[/color][color=#0000bb]arrint[/color][color=#007700].[/color][color=#0000bb]length[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]++){            for([/color][color=#0000bb]int j [/color][color=#007700]= [/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]j[/color][color=#007700]<=[/color][color=#0000bb]i[/color][color=#007700];[/color][color=#0000bb]j[/color][color=#007700]++){                if([/color][color=#0000bb]arrint[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]]<[/color][color=#0000bb]arrint[/color][color=#007700][[/color][color=#0000bb]j[/color][color=#007700]]){                    [/color][color=#0000bb]temp [/color][color=#007700]= [/color][color=#0000bb]arrint[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]];                    [/color][color=#0000bb]arrint[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]] = [/color][color=#0000bb]arrint[/color][color=#007700][[/color][color=#0000bb]j[/color][color=#007700]];                    [/color][color=#0000bb]arrint[/color][color=#007700][[/color][color=#0000bb]j[/color][color=#007700]]= [/color][color=#0000bb]temp[/color][color=#007700];                }            }        }        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"mang sau khi sap xep la: "[/color][color=#007700]);        for([/color][color=#0000bb]int i[/color][color=#007700]= [/color][color=#0000bb]0[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]<[/color][color=#0000bb]arrint[/color][color=#007700].[/color][color=#0000bb]length[/color][color=#007700];[/color][color=#0000bb]i[/color][color=#007700]++){            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#0000bb]arrint[/color][color=#007700][[/color][color=#0000bb]i[/color][color=#007700]]+[/color][color=#dd0000]" "[/color][color=#007700]);        }    }}[/color] 

</blockquote></div>
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câu 3:
mình chưa làm được

a ơi a giải thích cụ thể bài 1 cho e với đk không từ chỗ class sinhvien
xuống dưới ấy