最近做多人视频时设计了一个简单的类，但是简单的类也很能说明问题，也再次说明有些基础知识还是理解得不够深刻，刚写了个测试程序以便日后查阅，主要是关于返回值为引用类型时的一点测试:
#include <iostream> using namespace std; class CConstRef { public: CConstRef(int iA):m_iA(iA) { } const int& GetA()const { return m_iA; } int& GetA() { return m_iA; } void PrintAddress()const { cout<<"Address of m_iA = "<<&m_iA<<endl; } private: int m_iA; }; int main(int argc,char* argv[]) { //常量对象 const CConstRef cCA(8); //非常量对象 CConstRef CA(9); ////////////////////////////////////////////////////////////////////////// //注意下面的<a href="https://www.jb51.cc/tag/diaoyong/" target="_blank" class="keywords">调用</a>都是返回对象cCA的成员m_iA的引用,且此引用都是用来初始化另一引用 //因此地址都相同 //<a href="https://www.jb51.cc/tag/diaoyong/" target="_blank" class="keywords">调用</a>int& GetA() int& ra = CA.GetA(); CA.PrintAddress(); cout<<"Address of ra = "<<&ra<<endl; ra = 3; cout<<"<a href="https://www.jb51.cc/tag/Now/" target="_blank" class="keywords">Now</a> the CA.m_iA = "<<CA.GetA()<<endl; //<a href="https://www.jb51.cc/tag/diaoyong/" target="_blank" class="keywords">调用</a>int& GetA() const int& ra1 = CA.GetA(); cout<<"Address of ra1 = "<<&ra1<<endl; ////////////////////////////////////////////////////////////////////////// //<a href="https://www.jb51.cc/tag/diaoyong/" target="_blank" class="keywords">调用</a>int& GetA() int va = CA.GetA(); CA.PrintAddress(); cout<<"Address of va = "<<&va<<endl; va = 3; cout<<"<a href="https://www.jb51.cc/tag/Now/" target="_blank" class="keywords">Now</a> the CA.m_iA = "<<CA.GetA()<<endl; //<a href="https://www.jb51.cc/tag/diaoyong/" target="_blank" class="keywords">调用</a>int& GetA() const int va1 = CA.GetA(); cout<<"Address of va1 = "<<&va1<<endl; ////////////////////////////////////////////////////////////////////////// //下面的rb就是cCA.m_iA const int& rb = cCA.GetA(); cCA.PrintAddress(); cout<<"Address of rb = "<<&rb<<endl; /* error: invalid initialization of reference of type 'int&' from expression of type 'const int' 上面的<a href="https://www.jb51.cc/tag/cuowu/" target="_blank" class="keywords">错误</a>时G++<a href="https://www.jb51.cc/tag/tishi/" target="_blank" class="keywords">提示</a>的，这么说来其实编译器给我们返回的是const int而不是const int& */ // int& rb1 = cCA.GetA(); //下面的的vb和vb1都是是cCA.m_iA的<a href="https://www.jb51.cc/tag/yige/" target="_blank" class="keywords">一个</a>副本 const int vb = cCA.GetA(); cout<<"Address of vb = "<<&vb<<endl; int vb1 = cCA.GetA(); cout<<"Address of vb1 = "<<&vb1<<endl; vb1 = 10; cout<<"<a href="https://www.jb51.cc/tag/Now/" target="_blank" class="keywords">Now</a> the cCA.m_iA = "<<cCA.GetA()<<endl; return 0; }
下面是在MinGW的G++下输出的结果
路路漫漫其修远兮，吾将上下而求索！
