JavaSE之数组扩容

package com.atguigu4.search_sort.exer1;  
  
public class ArrayExer01_1 {  
    public static void main(String[] args) {  
        int[] arr = new int[]{1,2,3,4,5};  

        //扩容1倍容量  
        // int[] newArr = new int[arr.length * 2];  
        //或  
        int[] newArr = new int[arr.length << 1];  

        //将原有数组中的元素复制到新的数组中  
        for (int i = 0; i < arr.length; i++) {  

        newArr[i] = arr[i];  
        }  

        //将10,20,30三个数据添加到新数组中  
        newArr[arr.length] = 10;  
        newArr[arr.length + 1] = 20;  
        newArr[arr.length + 2] = 30;  

        //将新的数组的地址赋值给原有的数组变量  
        arr = newArr;  

        //遍历arr  
        for (int i = 0; i < arr.length; i++) {  
            System.out.print(arr[i] + "\t");  
        }  
    }  
}