java学习 --- 数组的应用

一、数组赋值机制

数组在默认情况下是引用传递，赋的值是地址。

package com.jun.demo01;

public class demo08 {
    public static void main(String[] args) {
        //基本数据传递
        int a = 10;
        int b = a ;
        b = 20;
        System.out.println("a=" + a);
        System.out.println("b=" + b);
        //数组是引用传递
        int[] arr1 = {1,2,3};
        int[] arr2 = arr1;
        arr2[0] = 4;
       //遍历数组
        for (int i = 0; i 

 二、内存图

 二、数组的拷贝

package com.jun.demo01;

public class demo09 {
    public static void main(String[] args) {
        //创建一个数组
        int[] arr1 = {1,2,3,4};
        int[] arr2 = new int[arr1.length];
        //遍历数组，将数据存入arr2
        for (int i = 0; i < arr1.length ; i++) {
            arr2[i] = arr1[i];
        }
        //修改arr2数据
        arr2[0] = 5;
        for (int i = 0; i < arr1.length ; i++) {
            System.out.print("arr1:" + arr1[i]);
        }
        System.out.println();
        for (int i = 0; i 

 三、数组翻转

方法一

package com.jun.demo01;

public class demo10 {
    public static void main(String[] args) {
        //定义一个数组
        int[] arr = {1,2,3,4,5,6};
        //用于接收数组的长度
        int len = arr.length;
        int num = 0;
        System.out.println("原始数组");
        for (int i = 0; i 

 方法二

package com.jun.demo01;

public class demo11 {
    public static void main(String[] args) {
        //定义一个数组
        int[] arr = {1,2,3,4,5,6};
        //创建一个新的数组
        int[] arr2 = new int[arr.length];
        for (int i = arr.length - 1,j = 0; i >= 0 ; i--,j++) {
            arr2[j] = arr[i];
        }
        System.out.println("翻转后的数组");
        //遍历数组
        for (int i = 0; i