java-数组的（增删查）

Posted 2022-05-26 zimo-bwl1029-s

1.查询元素

import java.util.Arrays;
import java.util.Scanner;

public class TestArry2 
    public static void main(String[] args) 
        //数组查询
        int arr[] = new int[]12, 34, 55, 11, 151;
        System.out.println(Arrays.toString(arr));
        System.out.println("输入要查找的数");
        Scanner scanner = new Scanner(System.in);
        int num = scanner.nextInt();
        int index = query(arr, num);
        if (index > 0) 
            System.out.println("索引为" + index);
         else 
            System.out.println("查无次数");
        


    

    public static int query(int arr[], int num) 
        int index = -1;
        for (int i = 0; i <= arr.length - 1; i++) 
            if (arr[i] == num) 
                index = i;
                break;
            
        
        return index;
    

2.添加元素

import java.util.Arrays;
import java.util.Scanner;

public class TestArry3 
    public static void main(String[] args)
    //添加元素
        int arr[]=new int[]12,43,65,77,11;
        System.out.println(Arrays.toString(arr));

        Scanner scanner=new Scanner(System.in);
        System.out.println("输入要添加的元素");
        int num=scanner.nextInt();
        System.out.println("输入要插入的索引位置");
        int n=scanner.nextInt();

        add(arr,n,num);
        System.out.println(Arrays.toString(arr));
    

    public static  void add(int arr[],int n,int num)
        for (int i=arr.length-1;i>=(n+1);i--)
            arr[i]=arr[i-1];
        
        arr[n]=num;
    

3.删除元素

import java.util.Arrays;
import java.util.Scanner;

public class TestArry4 

    public static void main(String[] args) 
        //删除元素
        int arr[] = new int[]12, 34, 56, 77, 100;
        System.out.println(Arrays.toString(arr));
        Scanner scanner = new Scanner(System.in);
        System.out.println("输入要删除的元素");
        int num = scanner.nextInt();
        int index = query(arr, num);
        delete(arr, index);
        System.out.println(Arrays.toString(arr));
    

    //查找索引
    public static int query(int arr[], int num) 
        int index = -1;
        for (int i = 0; i <= arr.length - 1; i++) 
            if (arr[i] == num) 
                index = i;
                break;
            
        
        return index;
    

    //删除元素
    public static void delete(int arr[], int index) 
        for (int i = index; i <= arr.length - 2; i++) 
            arr[i] = arr[i + 1];
        
        arr[arr.length - 1] = 0;