运算符重载、成员函数和友元函数举例（复数）

源程序：

#include <iostream>
using namespace std;

class myComplex
{
private:
double real, imag;
public:
myComplex();
myComplex(double r, double i);
void outCom();
myComplex operator-(const myComplex& c);
friend myComplex operator+(const myComplex& c1, const myComplex& c2);
};

myComplex::myComplex()
{
real = 0;
imag = 0;
}
myComplex::myComplex(double r, double i)
{
real = r;
imag = i;
}
void myComplex::outCom()
{
cout << "(" << real << "," << imag << ")";
}

myComplex myComplex::operator-(const myComplex& c)
{
return myComplex(this->real - c.real, this->imag - c.imag);
}

myComplex operator+(const myComplex& c1, const myComplex& c2)
{
return myComplex(c1.real + c2.real, c1.imag + c2.imag);
}

int main()
{
myComplex c1(1, 2), c2(3, 4), res;
c1.outCom();
cout << "operator+";
c2.outCom();
cout << "=";
res = c1 + c2; //调用运算符重载函数
res.outCom();
cout << endl;
c1.outCom();
cout << "operator-";
c2.outCom();
cout << "=";
res = c1 - c2; //调用运算符重载函数
res.outCom();
cout << endl;
return 1;
}