c++运算符重载

complex.h

#ifndef _COMPLEX_H_#define _COMPLEX_H_#include <iostream>using namespace std;class Complex{friend ostream& operator<<(ostream& out,const Complex& c);friend istream& operator>>(istream& input,Complex& c);friend Complex operator*(const Complex c1,const Complex c2);friend Complex operator/(const Complex c1,const Complex c2);friend Complex& operator++(Complex&c);//前缀friend Complex operator++(Complex&c,int);//后缀public:Complex(int x=1,int y=1):a(x),b(y){};Complex operator+(const Complex c);Complex operator-(const Complex c);Complex& operator--();//前缀Complex operator--(int);//后缀operator int();//只能是成员函数 不必写返回值类型 无形参 强制类型转换protected:private:int a;int b;};#endif/*不能重载的运算符只有5个：类属关系运算符“.”，成员指针运算符“*”，作用域分辨符“::”，sizeof运算符和三目运算符“?:”*/

Complex.cpp

#include "Complex.h"ostream& operator<<(ostream& out,const Complex& c){if (c.a==0){if (c.b==0)out<<"0";elseout<<c.b<<"i";}else if (c.b<0){out<<c.a<<c.b<<"i";}else  if(c.b==0){out<<c.a;}else{out<<c.a<<"+"<<c.b<<"i";}return out;}istream& operator>>(istream& input,Complex& c){cout<<"please input the a and b:";input>>c.a>>c.b;return input;}Complex Complex::operator +(const Complex c){return Complex(a+c.a,b+c.b);}Complex Complex::operator -(const Complex c){return Complex(a-c.a,b-c.b);}Complex operator*(const Complex c1,const Complex c2){int aa = c1.a*c2.a-c1.b*c2.b;int bb = c1.a*c2.b+c1.b*c2.a;return Complex(aa,bb);}Complex operator/(const Complex c1,const Complex c2){int aa = (c1.a*c2.a+c1.b*c2.b)/(c2.a*c2.a+c2.b*c2.b);int bb = (c1.b*c2.a+c1.a*c2.b)/(c2.a*c2.a+c2.b*c2.b);return Complex(aa,bb);}Complex& operator++(Complex&c){//前缀c.a +=10;return c;}Complex& Complex::operator --(){//前缀a -= 10;return *this;}Complex operator++(Complex&c,int){//后缀Complex old(c);c.a +=1;return old;}Complex Complex::operator --(int){//后缀Complex old(*this);a -= 1;return old;}Complex::operator int(){return a;}

main.cpp

#include "complex.h"#include <iostream>using namespace std;int main(){cout<<"hello world!"<<endl;Complex c(1,2);cout<<"c="<<c<<endl;Complex cc;cin>>cc;cout<<"cc="<<cc<<endl;cout<<"cc+c="<<cc+c<<endl;cout<<"cc-c="<<cc-c<<endl;cout<<"cc*c="<<cc*c<<endl;cout<<"cc/c="<<cc/c<<endl;cout<<"++cc="<<++cc<<endl;cout<<"--c="<<--c<<endl;cout<<"cc++="<<cc++<<endl;cout<<"cc="<<cc<<endl;cout<<"c--="<<c--<<endl;cout<<"c="<<c<<endl;cout<<"int(c)="<<int(c)<<endl;return 0;}