2020.4.14 java第四次作业

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 java_test;

import java.util.Scanner;

public class test_5 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner input=new Scanner(System.in);
        System.out.println("请输入数组的值");
        int[]arr = new int[5];
        for (int i = 0; i < arr.length; i++) {
            arr[i] = input.nextInt();
        }
        for (int i = 0; i < arr.length-1; i++) {
            for (int j = 0; j < arr.length-1-i; j++) {
                if (arr[j]>arr[j+1]) {
                    int temp = arr[j];
                    arr[j] = arr[j+1];
                    arr[j+1] = temp;
                }
            }
        }
        System.out.println("冒泡排序后输出为：");
        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 java_test;

import java.util.Scanner;

public class test_5 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int[]a = new int [] {34,22,35,67,45,66,12,33};
        Scanner input=new Scanner(System.in);
        System.out.println("输入想查询的数字");
        int i=input.nextInt();
        int b = 0;
        for (int j = 0; j < a.length; j++) {
            if (a[j]==i) {
                System.out.println("该数存在于数组中下标为" +j);
                b=1;
            }
        }
        if (b==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 java_test;

import java.util.Scanner;

public class test_5 {
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        double[][]arr={{1,1,1,1},{2,2,2,2},{3,3,3,3},{4,4,4,4},{5,5,5,5}};
        for(int i=0;i<arr.length;i++){
           System.out.println();
           for(int j=0;j<arr[i].length;j++){
               System.out.print(arr[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 java_test;

import java.util.Scanner;

public class test_5 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
          int[][]arr={{20,30,40,45},{89,56,12,50},{44,33,22,11}};
          int max=arr[0][0];
          for (int i = 0; i < arr.length; i++) {
            for (int j = 0; j < arr.length; j++) {
                if (arr[i][j]>max) {
                    max=arr[i][j];
                }
            }
        }
          System.out.println("其中的最大值为：" + max);
    }

}

package java_test;
import java.util.Scanner;
public class test_5 {
public static void main(String[] args) {// TODO Auto-generated method stub/*Scanner input=new Scanner(System.in);System.out.println("请输入数组的值");int[]arr = new int[5];for (int i = 0; i < arr.length; i++) {arr[i] = input.nextInt();}for (int i = 0; i < arr.length-1; i++) {for (int j = 0; j < arr.length-1-i; j++) {if (arr[j]>arr[j+1]) {int temp = arr[j];arr[j] = arr[j+1];arr[j+1] = temp;}}}System.out.println("冒泡排序后输出为：");for (int i = 0; i < arr.length; i++) {System.out.println(arr[i] + " ");}int[]a = new int [] {34,22,35,67,45,66,12,33};Scanner input=new Scanner(System.in);System.out.println("输入想查询的数字");int i=input.nextInt();int b = 0;for (int j = 0; j < a.length; j++) {if (a[j]==i) {System.out.println("该数存在于数组中下标为" +j);b=1;}}if (b==0) {System.out.println("not found");}double[][]arr={{1,1,1,1},{2,2,2,2},{3,3,3,3},{4,4,4,4},{5,5,5,5}};        for(int i=0;i<arr.length;i++){           System.out.println();           for(int j=0;j<arr[i].length;j++){           System.out.print(arr[i][j]+" ");           }        }*/  int[][]arr={{20,30,40,45},{89,56,12,50},{44,33,22,11}};          int max=arr[0][0];          for (int i = 0; i < arr.length; i++) {for (int j = 0; j < arr.length; j++) {if (arr[i][j]>max) {max=arr[i][j];}}}          System.out.println("其中的最大值为："max);}
}