自考新教材--p152

源程序：

//"+"、"-"运算符重载

#include <iostream>

using namespace std;

class myComplex

{

private:

　　double real, imag;

public:

　　myComplex();

　　myComplex(double x, double i);

　　void outCom();

　　myComplex operator-(const myComplex &c);

　　friend myComplex operator+(const myComplex &c1, const myComplex &c2);//声明友元函数

};

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)//友元函数可以直接在类外定义

{

　　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;

　　res.outCom();

　　cout << endl;

　　c1.outCom();

　　cout << "operator-";

　　c2.outCom();

　　cout << "=";

　　res = c1 - c2;

　　res.outCom();

　　cout << endl;

　　system("pause");

　　return 1;

}

运行结果：

自考新教材--p152

原文：https://www.cnblogs.com/duanqibo/p/12059875.html