C++之输入输出运算符重载

friendostream&operato<<(ostream&os,constRIGHT&right){...}ostream,标准库的类 cout<<a;//operator<<(cout,a)

friendistream&operato>>(istream&is,RIGHT&right){...}istream cin;//istream是标准库的类cin>>a;//operator>>(cin,a)

• 因为无法向标准库类添加成员函数，所以只能使用全局函数的形式

#include<iostream>usingnamespacestd;classComplex{private:doubler;doublei;public:Complex(doubler,doublei){this->r=r;this->i=i;}constComplexoperator+(constComplex&c){Complextmp(r+c.r,i+c.i);returntmp;}Complex&operator+=(constComplex&c){r=r+c.r;i=i+c.i;return*this;}friendostream&operator<<(ostream&os,constComplex&c){os<<c.r<<" + "<<c.i<<"i"<<endl;returnos;// cout << a << b << c << endl;}friendistream&operator>>(istream&is,Complex&c){is>>c.r>>c.i;returnis;}friendconstComplexoperator-(constComplex&l,constComplex&r);friendComplex&operator-=(Complex&L,constComplex&R);};constComplexoperator-(constComplex&l,constComplex&r){Complextmp(l.r-r.r,l.i-r.i);returntmp;}Complex&operator-=(Complex&L,constComplex&R){L.r-=R.r;L.i-=R.i;returnL;}intmain(void){Complexc1(2,3);cout<<c1;Complexc2(0,0);cin>>c2;cout<<c2;return0;}