C＃==运算符详细说明了什么？ [英] C# what does the == operator do in detail?

问题描述

在c＃中，当你在两个对象上与==运算符进行比较时，后台究竟会发生什么？它只是比较地址？或者像Equals（）或CompareTo（）那样？

in c# what does exactly happen in the background when you do a comparison with the "==" operator on two objects? does it just compare the addresses? or does it something like Equals() or CompareTo() ?

PS：java中的==运算符怎么样？它的行为是否相同？

PS: what about the "==" operator in java? does it behave the same?

推荐答案

据我所知：

• 它按值（相等）比较值类型


• 它按引用比较引用类型（标识）


• 除外如果==运算符重载，则调用该运算符。

Equals在object中实现，也可以重写。 Object中的默认实现执行引用类型的引用比较。所以默认情况下，Equals和==都是一样的。

Equals is implemented in object and can be overridden as well. The default implementation in Object performs a reference comparison for reference types. So by default, Equals and == do the same.

我认为在java中你不能重载==运算符。但是我的Java知识已经过时了。

I think in java you cannot overload the == operator. But my Java knowledge is pretty outdated.

编辑：
请注意 == operator是一个静态方法。它在编译时绑定，基于变量或字段的类型。 Equals 是一个在运行时根据实际运行时类型找到的虚方法。

Note that the == operator is a static method. It is bound at compile time, base on the types of your variables or fields. Equals is a virtual method that is found at runtime, based on actual runtime types.

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