第9周项目1-复数类中的运算符重载（续）

问题描述：

在复数类中的运算符重载基础上
（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。

代码：

#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);
    Complex operator+(const double d);
    Complex operator-(const double d);
    Complex operator-();
    friend istream& operator>>(istream& input,Complex& c);
    friend ostream& operator<<(ostream& output,Complex& c);
    void display();
private:
    double real;
    double imag;
};
//下面定义成员函数
istream& operator>>(istream& input,Complex& c)
{
    char i;
    cin>>c.real>>c.imag>>i;
    return input;
}
ostream& operator<<(ostream& output,Complex& c)
{
    cout<<c.real;
    if(c.imag>0) cout<<"=";
    cout<<c.imag<<"i";
    return output;
}
Complex Complex::operator-()
{
    return Complex(-real,-imag);
}
void Complex::display()
{
    cout<<"("<<real<<","<<imag<<"i)"<<endl;
}
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 Complex::operator+(const double d)
{
    return Complex(real+d,imag);
}
Complex Complex::operator-(const double d)
{
    return Complex(real-d,imag);
}

//下面定义用于测试的main()函数
int main()
{
    Complex c1,c2,c3;
    cin>>c1>>c2;
    cout<<"c1="<<c1<<endl;
    cout<<"c2="<<c2<<endl;
    c3=-c1;
    cout<<c3<<endl;
    return 0;
}

运行结果：