什么是朋友ostream [英] What is friend ostream

问题描述

对于这一行代码在我的头文件中到底意味着什么，我有些困惑.

I'm a bit confused about what exactly this line of code means in my header file.

friend ostream & operator << (ostream &, const something &);

有人可以为我澄清吗?

推荐答案

该行代码表明运算符<<是某物的朋友(因为它已在某物类定义中列出).这意味着该运算符<<函数可以访问其中的变量.

That line of code says that the operator << is a friend of something (since it's listed in the something class definition). This means that that operator << function can access the variables inside there.

&这里的参数表示您在调用方法时传递对象，而这些参数将只是这些参数对象的另一个名称.返老还童表示您将返回ostream参数，以便可以连接<<表达式一起使用时，避免使用一个全局cout时避免创建新的"cout".

The & here as the parameters mean that you pass in objects when calling the method and those parameters will just be another name for those parameter objects. Returning ostream & means that you're going to return the ostream parameter so that you can connect << expressions together avoiding creating a new "cout" when using the one global cout is what is needed.

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