Java中的数组分配和参考 [英] Array assignment and reference in Java

问题描述

public class Test {
    public static void main(String[] args) {
        int[] a = {1, 2, 3, 4, 5};
        int[] b = a;
        int[] c = {6, 7, 8};
        a = c;
        for(int i = 0; i < a.length; i ++)
            System.out.print(a[i] + " ");
        System.out.print("\n");
        for(int i = 0; i < b.length; i ++) 
            System.out.print(b[i] + " ");
        System.out.print("\n");
    }
}

我已经初始化了数组a，并将a的引用分配给新数组b.现在，我初始化了一个新的数组c并将其引用传递给数组a.由于数组b是对数组a的引用，因此b应该具有c中的新值，但是b具有a的旧值.背后的原因是什么? 输出在下面给出-

I have initialized array a and assigning reference of a to new array b. Now I initialized a new array c and passed its reference to array a. Since array b is reference to array a, b should have new values that are in c but b is having old values of a. What is the reason behind it? Output is given below -

输出-

6 7 8 
1 2 3 4 5

推荐答案

不要被名称"list"所打扰.图像取自python可视化，但是原理在Java中是相同的

数组a被分配了一个新数组:

Array a is assigned with a new array:

将数组b分配给a之后的实例:

Array b is assigned to the instance behind a:

数组c被分配了一个新数组:

Array c is assigned with a new array:

最后将a分配给c之后的实例，b未被重新分配，并且仍然保留对旧a的引用:

And finally a is assigned to the instance behind c, b was not re-assigned and still keeps a reference to the old a:

图像取自pythontutor.com上的可视化图像

这篇关于Java中的数组分配和参考的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！