C++ 通过引用来传递和返回对象

提高效率

#include<iostream>using namespace std;class C{public:void set(int n){num=n;}int get() const {return num;}private:int num;};void f(C& );C& g();int main(){C c1, c2;f(c1);c2=g();cout<<c2.get()<<endl;cout<<"***************"<<endl;cout<<c1.get()<<endl<<c2.get()<<endl;return 0;}void f(C& c){c.set(-999);cout<<c.get()<<endl;}C& g(){static C c3;c3.set(123);return c3;}