java 交换两个整数的函数
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Function that swaps two integers
提问by Armen Tsirunyan
Possible Duplicate:
How to write a basic swap function in Java
可能的重复：
如何用 Java 编写基本的交换函数
Hi. I don't know java at all, and in the near future have no wish to study it. However I have lots of friends that are java programmers and from conversations I learnt that there is no analog of C#'s ref keyword in Java. Which made me wonder how can one write a function that swaps two integers in Java. My friends (though not very good java experts) could not write such a function. Is it officially impossible? Please note, that I understand that one can swap two integers without a function, the question is exactly to write a function that takes two integers and swaps them. Thanks in advance.
你好。完全不懂java，近期也不想学。但是，我有很多 Java 程序员朋友，并且从对话中我了解到 Java 中没有类似于 C# 的 ref 关键字。这让我想知道如何在 Java 中编写一个交换两个整数的函数。我的朋友（虽然不是很好的java专家）写不出这样的函数。官方是不可能的吗？请注意，我知道一个人可以在没有函数的情况下交换两个整数，问题正是编写一个接受两个整数并交换它们的函数。提前致谢。
回答by Lie Ryan
Short: You can't.
简短：你不能。
Long: You need some workaround, like wrapping them in a mutable datatype, e.g. array, e.g.:
Long：您需要一些解决方法，例如将它们包装在可变数据类型中，例如数组，例如：
public static void swap(int[] a, int[] b) {
int t = a[0]; a[0] = b[0]; b[0] = t;
}
but that doesn't have the same semantic, since what you're swapping is actually the array members, not the a and b themselves.
但这没有相同的语义，因为您交换的实际上是数组成员，而不是 a 和 b 本身。
回答by Kru
In Java, all the arguments are passed by value. So there is no such thing as a ref.
在 Java 中，所有参数都是按值传递的。所以没有ref.
However, you might achieve variable swapping by wapping values in objects (or arrays).
但是，您可以通过交换对象（或数组）中的值来实现变量交换。
public class Holder<T> {
public T value = null;
public Holder(T v) { this.value = v; }
}
public static <T> void swap(Holder<T> a, Holder<T> b) {
T temp = a.value; a.value = b.value; b.value = temp;
}
