C++之输入输出运算符重载

我在人间贩卖青春2026-02-10 11:30

cpp 复制代码

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

cpp 复制代码

friend istream& 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

cpp 复制代码

#include <iostream>
using namespace std;
class Complex{
private:
    double r;
    double i;
public:
    Complex(double r, double i){
        this->r = r;
        this->i = i;
    }
    const Complex operator+(const Complex& c){
        Complex tmp(r+c.r, i+c.i);
        return tmp;
    }
    Complex & operator+=(const Complex &c){
        r = r + c.r;
        i = i + c.i;
        return *this;
    }
    friend ostream& operator<<(ostream &os, const Complex& c){
        os << c.r << " + " << c.i << "i" << endl;
        return os; // cout << a << b << c << endl;
    }
    friend istream& operator>>(istream &is, Complex& c){
        is >> c.r >> c.i ;
        return is;
    }
    friend const Complex operator-(const Complex& l , const Complex& r);
    friend Complex & operator-=(Complex &L, const Complex &R);
};
const Complex operator-(const Complex& l, const Complex& r){
        Complex tmp(l.r - r.r, l.i - r.i);
        return tmp;
}
    Complex & operator-=(Complex &L, const Complex &R){
        L.r -= R.r;
        L.i -= R.i;
        return L;
    }
int main(void){
    Complex c1(2,3);
    cout << c1;
    Complex c2(0,0);
    cin >> c2;
    cout << c2;
    return 0;
}