C++中友元（友元函数和友元类）的用法和功能

时间 2020-05-14

标签 c++ 函数用法功能栏目 C&C++ 繁體版

原文原文链接

采用类的机制后实现了数据的隐藏与封装，类的数据成员通常定义为私有成员，成员函数通常定义为公有的，依此提供类与外界间的通讯接口。可是，有时须要定义一些函数，这些函数不是类的一部分，但又须要频繁地访问类的数据成员，这时能够将这些函数定义为该函数的友元函数。除了友元函数外，还有友元类，二者统称为友元。友元的做用是提升了程序的运行效率（即减小了类型检查和安全性检查等都须要时间开销），但它破坏了类的封装性和

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1. C++友元的用法(友元函数、友元类和友元成员函数)
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3. C++ 类(友元函数和友元类)
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