第六周作业

1.定义长度为5的整型数组,输入他们的值,用冒泡排序后输出

package pra;
import java.util.Scanner;
public class Text1 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int [] a = new int [5];
        Scanner input = new Scanner(System.in);
        for (int i = 0; i < a.length; i++) {
            System.out.println("请输入第" + (i + 1) + "个数字");
            a[i] = input.nextInt();
        }
        for (int i = 0; i < a.length; i++) {
            for(int j = 0; j < a.length -1 -i; j++) {
                int num = 0;
                if(a[j] > a[j + 1]) {
                    num = a[j];
                    a[j] = a[j + 1];
                    a[j + 1] = num;
                }
            }
        }
            
        
        for(int i : a) {
            System.out.print(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 pra;
import java.util.Scanner;
public class Text1 {

    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("请输入要查找的数字");
        int b = input.nextInt();
        for (int i = 0; i < a.length; i++) {
            if(b == a[i]) {
                System.out.println("数字" + b + "的下标是：" + i);
                return;
            }
        }
        System.out.println("not found");
        return;
        
        
        
        
    }

}

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 pra;
import java.util.Scanner;
public class Text1 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        double[][] a = {{5, 4, 8, 1}, {8, 9, 6, 3}, {5, 7, 1, 3}, {2, 4, 5, 7}, {6, 3, 9, 5}};
        for (int i = 0; i < a.length; i++) {
            System.out.println();
            for (int j = 0; j < a[i].length; j++) {
                System.out.print(a[i][j] + "  ");
            }
        }
        
        
        
        
    }

}

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 pra;
import java.util.Scanner;
public class Text1 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int[][] a = {{5, 4, 8, 10}, {8, 9, 6, 52}, {5, 7, 1, 140}};
        int max = a[0][0];        
        for (int i = 0; i < a.length; i++) {
            for (int j = 0; j < a[i].length; j++) {
                if (a[i][j] > max) {
                    max = a[i][j];
                }
            }
        }
        System.out.println("最大值为" + max);
        
        
        
        
    }

}