使用友元函数形式进行运算符重载

#include <iostream> using namespace std; class Complex { private:     int real;     int p_w_picpath; public:     Complex(int real=0,int p_w_picpath=0):real(real),p_w_picpath(p_w_picpath)     {         cout<<"Complex::Complex():"<<this<<endl;     }     Complex(const Complex &x):real(x.real),p_w_picpath(x.p_w_picpath)     {         cout<<"Complex::Complex(Complex &):"<<this<<endl;     }     ~Complex()     {         cout<<"Complex::~Complex():"<<this<<endl;     }     friend Complex operator+(Complex &a,Complex &b);     friend Complex operator-(Complex &a,Complex &b);     void show(); }; Complex operator+(Complex &a,Complex &b) {     return Complex(a.real+b.real,a.p_w_picpath+b.p_w_picpath); } Complex operator-(Complex &a,Complex &b) {     return Complex(a.real-b.real,a.p_w_picpath-b.p_w_picpath); } void Complex::show() {     cout<<real;     if(p_w_picpath>0)         cout<<"+";     cout<<p_w_picpath<<"i"<<endl; } int main(int argc, char *argv[]) {     Complex a(10,20);     Complex b(70,80);     Complex c=a+b;     Complex d=a-b;     a.show();     b.show();     c.show();     d.show();     return 0; }