第9周项目1-复数类中的运算符重载（续）

/*
 *All rights reserved.
 *文件名称:main.cpp
 *作        者:姜 甜 甜
 *完成日期:2015年5月8日
 *版  本  号:v1.0
 *
 *问题描述:在<a target=_blank href="http://blog.csdn.net/sxhelijian/article/details/45172591" target="_blank">复数类中的运算符重载</a>基础上
（1）再定义一目运算符 -，-c相当于0-c。
（2）定义Complex类中的<<和>>运算符的重载，实现输入和输出，改造原程序中对运算结果显示方式，使程序读起来更自然。
*/

#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);
    friend Complex operator -(const Complex &c);
    friend istream &operator >>(istream &input,Complex &c);
    friend ostream &operator <<(ostream &output,Complex &c);
private:
    double real;
    double imag;
};
Complex operator+(const Complex &c1,const Complex &c2)
{
    return Complex(c1.real+c2.real,c1.imag+c2.imag);
}
Complex operator-(const Complex &c1,const Complex &c2)
{
    return Complex(c1.real-c2.real,c1.imag-c2.imag);
}
Complex operator*(const Complex &c1,const Complex &c2)
{
    return Complex(c1.real*c2.real-c1.imag*c2.imag,c1.real*c2.imag+c1.imag*c2.real);
}
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;
}
Complex operator -(const Complex &c)
{
    return Complex(-c.real,-c.imag);
}
istream &operator >>(istream &input,Complex &c)
{
    char s1,s2;
    double a,b;
    while(1)
    {
    cout<<"input a complex number(a+bi或a-bi):";
    input>>a>>s1>>b>>s2;
    if((s1=='+'||s1=='-')&&s2=='i')
        break;
    else
        cout<<"格式错误，再次输入：\n";
    }
    c.real=a;
   c.imag=(s1=='+')?b:-b;
    return input;
}
ostream &operator <<(ostream &output,Complex &c)
{
    output<<c.real;
    if(c.imag>0)
        cout<<"+";
    output<<c.imag<<"i"<<endl;
    return output;
}
int main()
{
    Complex c1,c2,c3;
    cout<<"c1:";
    cin>>c1;
    cout<<"c1="<<c1;
    cout<<"c2:";
    cin>>c2;
    cout<<"c2="<<c2;
    c3=c1+c2;
    cout<<"c1+c2="<<c3;
    c3=c1-c2;
    cout<<"c1-c2="<<c3;
    c3=c1*c2;
    cout<<"c1*c2="<<c3;
    c3=c1/c2;
    cout<<"c1/c2="<<c3;
    return 0;
}