Java数组动态扩容和动态缩减

package com;
import java.lang.String;
import java.util.Scanner;
public class Linghu {
    public static void main(String []args){
       int arr[]={1,2,3};
        Scanner myScanner = new Scanner(System.in);
        do{
            System.out.println("请输入需要添加的元素");
           int arrNew[]=new int[arr.length+1];
            int addNum=myScanner.nextInt();
           for (int i=0;i<arr.length;i++){
               arrNew[i]=arr[i];
           }
           arrNew[arrNew.length-1]=addNum;
           arr=arrNew;
           System.out.println("=======元素输出为：");
           for (int j=0;j<arr.length;j++){
               System.out.print(arr[j]+"\t");
           }
            System.out.println("是否继续添加元素？y/n");
           char key=myScanner.next().charAt(0);
           if(key=='n') break;
       }while(true);
    }
}

package com;
import java.lang.String;
import java.util.Scanner;
public class Linghu {
    public static void main(String []args){
      int arr[]={1,2,3};
        Scanner myScanner = new Scanner(System.in);
        do{
            //System.out.println("输入需要添加的新元素:");
          int arrNew[]= new int [arr.length-1];
          //int addNum=myScanner.nextInt();
          for (int i=0;i<arr.length-1;i++){
              arrNew[i]=arr[i];
          }
          //arrNew[arrNew.length-1]=addNum;
          arr=arrNew;//arr的指针指向arrNew
            System.out.println("缩减后的数组元素为：");
          for (int j=0;j<arr.length;j++){
              System.out.print(arr[j]+"\t");
          }
            System.out.println("是否需要缩减元素？Y/N");
          char key=myScanner.next().charAt(0);
          if(key=='n') break;
      }while(true);
    }
}