第八周上机实践项目1-实现复数类中的运算符重载（友元函数）

/*
 *Copyright  (c)  2014,烟台大学计算机学院
 *All rights reserved.
 *文件名称: test.cpp
 *作        者:满星辰
 *完成日期:2015 年 4 月 28 日
 *版本号:v1.0
 *
 *问题描述:请用类的友元函数，而不是成员函数，再次完成定义复数类重载运算符+、-、*、/，使之能用于复数的加减乘除；
 *输入描述:
 *程序输出:
 */
#include <iostream>
using namespace std;
class Complex
{
public:
    Complex(){real=0;imag=0;}
    Complex(double r,double i){real=r; imag=i;}
    friend Complex operator+(const Complex &c1,const Complex &c2);
    friend Complex operator-(const Complex &c1,const Complex &c2);
    friend Complex operator*(const Complex &c1,const Complex &c2);
    friend Complex operator/(const Complex &c1,const Complex &c2);
    void display();
private:
    double real;
    double imag;
};
//下面定义成员函数
void Complex::display()
{
    cout<<"("<<real<<","<<imag<<"i"<<")"<<endl;
}
Complex operator+(const Complex &c1,const Complex &c2)
{
    Complex c;
    c.real=c1.real+c2.real;
    c.imag=c1.imag+c2.imag;
    return c;
}
Complex operator-(const Complex &c1,const Complex &c2)
{
    Complex c;
    c.real=c1.real-c2.real;
    c.imag=c2.imag-c2.imag;
    return c;
}
Complex operator * (const Complex &c1,const Complex &c2)
{
    Complex c;
    c.real=c1.real*c2.real-c1.imag*c2.imag;
    c.imag=c1.real*c2.imag+c1.imag*c2.real;
    return c;
}
Complex operator / (const Complex &c1,const Complex &c2)
{
    Complex c;
    c.real=(c1.real*c2.real+c1.imag*c2.imag)/(c2.real*c2.real+c2.imag*c2.imag);
    c.imag=(c1.imag*c2.real-c1.real*c2.imag)/(c2.real*c2.real+c2.imag*c2.imag);
    return c;
}
//下面定义用于测试的main()函数
int main()
{
    Complex c1(3,4),c2(5,-10),c3;
    cout<<"c1=";
    c1.display();
    cout<<"c2=";
    c2.display();
    c3=c1+c2;
    cout<<"c1+c2=";
    c3.display();
    c3=c1-c2;
    cout<<"c1-c2=";
    c3.display();
    c3=c1*c2;
    cout<<"c1*c2=";
    c3.display();
    c3=c1/c2;
    cout<<"c1/c2=";
    c3.display();
    return 0;
}

图片：

心得：

一开始我想的过于简单，只在类内声明时在函数前面加个friend 再在函数定义时把Complex::去掉。。。

然后就报错。。。看错误才想起这是友元函数，没有*this指针，需要两个参数才能实现两个数之间的关系