将数组分配给新变量，更改原始变量更改新变量 [英] Assigning Array to new variable, changing original changes the new one

问题描述

int[] test = {0,1,2,3,4,5};
    int[] before = test;
    System.out.println(before[2]);
    test[2] = 65;
    System.out.println(before[2]);

第一个 System.out 打印 2，它应该，但第二个打印 65.我已经用这种语言编程一年多了，据我所知，这不会发生！有什么帮助吗?

The first System.out prints 2 and it should, but the second prints 65. I have been programming for over a year in this language and as far as I know this is NOT suppose to happen! Any help?

    int first = 9;
    int second = first;
    System.out.println(second);
    first = 10;
    System.out.println(second);

上面的代码在两行打印9.

The code above prints 9 on both lines.

推荐答案

当你做before = test;时，before只是对test数组的引用，NO 新数组已创建并分配给 test.因此，当您查看 before[i] 的值时，您基本上是在查看 test[i] 的值，反之亦然.before 只是test 的别名.这就是为什么在第二次打印中你得到 65.

When you do before = test;, before is just a reference to test array, NO new array has been created and assigned to test. So when you look the value of before[i] you basically look at the value of test[i] and vice versa. before is just an alias of test. That's why in the second print you get 65.

查看Thinking in Java中的文本强>书，它一定会帮助你.

Check this text from Thinking in Java book, it will definitely help you.

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