JAVA第六周作业

1.定义长度为5的整型数组,输入它们的值,用冒泡排序输出

import java.util.Scanner;

public class Test02 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int[] num = new int[5];
        Scanner input = new Scanner(System.in);
        for (int i = 0; i < num.length; i++) {
            System.out.print("请输入第" + (i + 1) + "个数:");
            num[i] = input.nextInt();
        }
        for (int i = 0; i < num.length - 1; i++) {
            for (int j = 0; j < num.length - 1 - i; j++) {
                if (num[j] > num[j + 1]) {
                    int temp = num[j];
                    num[j] = num[j + 1];
                    num[j + 1] = temp;
                }
            }
        }
        for (int i = 0; i < num.length; i++) {
            System.out.print(num[i] + " ");
        }

    }

}

2.定义数组{34,22,35,67,45,66,12,33},输入一个数a,查找在数组中是否存在,如果存在输出下标,不存在输出"not found"

package one;

import java.util.Scanner;

public class Test02 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub

        int[] a = { 34, 22, 35, 67, 45, 66, 12, 33 };
        Scanner input = new Scanner(System.in);
        System.out.println("请输入一个数:");
        int b = input.nextInt();
        int xiabiao = -1;
        for (int i = 0; i < a.length; i++) {
            if (a[i] == b) {
                xiabiao = i;
                System.out.println(i);
                break;
            }

        }
        if (xiabiao == -1)
            System.out.println("not found");
    }

}

3.以矩阵的形式输出一个double型二维数组（长度分别为5、4，值自己设定）的值

package one;

public class Test02 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub

        double[][] a = { { 1, 2, 3, 4 }, { 5, 6, 7, 8 }, { 9, 10, 11, 12 }, { 13, 14, 15, 16 }, { 17, 18, 19, 20 } };
        for (int i = 0; i < 5; i++) {
            for (int j = 0; j < 4; j++) {
                System.out.print(a[i][j] + " ");
            }
            System.out.println();
        }
    }

}

4.定义一个二维数组(长度分别为3,4,值自己设定),求该二维数组的最大值

package one;

public class Test02 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub

        int[][] a = { { 10, 20, 30, 40 }, { 80, 70, 60, 50 }, { 90, 100, 110, 120 } };
        int max = 0;
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 4; j++) {
                if (a[i][j] > max) {
                    max = a[i][j];
                }
            }

        }
        System.out.println(max);
    }

}