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.

public class homework
{
    public static void main(String[] args) {
           int[] arr = {3,5,9,7,1};
           for (int i = 0; i < arr.length; i++) {
               for (int j = 0; j < arr.length-1-i; j++) {
               int num = 0;
               if(arr[j] > arr[j+1]){
                   num = arr[j];
                   arr[j]= arr[j+1];
                   arr[j+1] = num;
                }
             }
           }
           for (int i : arr) {
               System.out.println(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"

public class homework {
    public static void main(String[] args) {
        Scanner input=new Scanner(System.in);
        boolean  A=false;
        int[] x=new int[]{34,22,35,67,45,66,12,33};
        System.out.print("请输入需要查找的数");
        int a=input.nextInt();
        for(int i=0;i<x.length;i++){
            if(x[i]==a){
                System.out.println("该数存在于数组中下标为"+i);
                 A=true;
            }
        } if(A==false){
            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。

public class homework 
{
    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[i].length; 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

public class homework
{
    public static void main(String[] args) 
{
        int arr[][]={{1,2,3},{4,5,6},
                {7,8,9},{10,11,12}};
        int max=arr[0][0];
        for(int i=0;i<arr.length;i++){
            for(int j=0;j<arr[i].length;j++){
                if(arr[i][j]>max){
                    max=arr[i][j];
                }
            }
        }
        System.out.println("数组的最大值为"+max);
   }
}