第六周作业2

1.定义长度位5的整型数组，输入他们的值用冒泡排序后输

package li;
import java.util.Scanner;
public class test6{

    public static void main(String[] args) {
    int[] arr= new int [5];
    Scanner sc = new Scanner(System.in);
    System.out.println("依次输入数组中各元素的值");
    for (int i = 0; i < arr.length; i++) {
        arr[i]=sc.nextInt();
    }
    for (int i = 0; i < arr.length-1; i++) {
        for (int j = 0; i < arr.length-i-1; j++) {    
            if(arr[j]>arr[j+1]){
                int x=arr[j];
                arr[j]=arr[j+1];
                arr[j+1]=x;
            }
        }
    }
    for (int i = 0; i < arr.length; i++) {
        System.out.println(arr[i]+"");
        
    }
    }
}

2定义数组{34,22,35,67 ,45,66,12,33}输入-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 li;
import java.util.Scanner;
public class test6{

    public static void main(String[] args) {
        int[] arr= { 34, 22, 35, 67, 45, 66, 12, 33 };
        Scanner sc = new Scanner(System.in);
        System.out.println("输入数字，查找它是否在数组中");
        int x = sc.nextInt();
        int y = 0;
        for (int i = 0; i < arr.length; i++) {
        if (x == arr[i]) {
        System.out.println("下标为：" + i);
        y=1;
        }
        }
        if (y == 0) {
        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 li;
import java.util.Scanner;
public class test6{

    public static void main(String[] args) {
        double [][] arr={{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<arr.length;i++){
            for(int j=0;j<arr.length-1;j++){
                System.out.print(arr[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 li;
import java.util.Scanner;
public class test6{

    public static void main(String[] args) {
        int [][] arr={{20,31,51,5},{40,21,25,36},{52,36,92,41}};
        int max=arr[0][0];
        for(int i=0;i<arr.length;i++){
            for(int j=0;j<arr.length+1;j++){
                if(arr[i][j]>max){
                    max=arr[i][j];
                }
            }
        }
        System.out.println("二维数组最大值为："+max);

    }

}