JAVA数组元素的基本操作------JAVA入门基础教程

public class ARex
{
    public static void main(String[] args)
    {
        int[] arr = new int[]{1,2,3,4,5};
        int[] arr1 = new int[arr.length << 1];
        for (int i = 0; i < arr.length; i++)
        {
            arr1[i] = arr[i];
        }

        arr1[arr.length] = 10;
        arr1[arr.length+1] = 20;
        arr1[arr.length+2] = 30;
        arr = arr1;

        for (int i = 0; i < arr.length; i++)
        {
            System.out.print(arr[i]+"\t");
        }
        System.out.println();
        int[] arr2 = {1,2,3,4,5,6,7};
        int deleteIndex = 4;
        //不新建数组
        for (int i = deleteIndex; i < arr2.length - 1; i++)
        {
            arr2[i] = arr2[i + 1];
        }
        //修改最后元素
        arr2[arr2.length - 1] = 0;
        for (int i = 0; i < arr2.length; i++)
        {
            System.out.print(arr2[i] + "\t");
        }
        System.out.println();
        
        //方法2
        int[] newArr = new int[arr.length - 1];
        for (int i = 0; i < deleteIndex; i++)
        {
            newArr[i] = arr[i];
        }

        for (int i = deleteIndex; i < arr.length-1;i++)
        {
            newArr[i] = arr[i + 1];
        }

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