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
/** Copyright (c) 2015,烟台大学计算机学院* All right reserved.* 作者：赵嵩* 文件：Demo.cpp* 完成时间：2015年05月16日* 版本号：v1.0*/#include <iostream>using namespace std;class Complex{public:Complex(){real=0;imag=0;}Complex(double r,double i){real=r;imag=i;}friend ostream& operator << (ostream& output, const Complex& c);friend istream& operator >> (istream& input, Complex& c);Complex operator-();Complex operator+(const Complex &c2);Complex operator-(const Complex &c2);Complex operator*(const Complex &c2);Complex operator/(const Complex &c2);void display();private:double real;double imag;};//下面定义成员函数ostream& operator << (ostream& output, const Complex& c){output<<"("<<c.real;if(c.imag>=0) output<<"+";output<<c.imag<<"i)";return output;}istream& operator >> (istream& input, Complex& c){int a,b;char sign,i;do{cout<<"input a complex number(a+bi或a-bi):";input>>a>>sign>>b>>i;}while(!((sign=='+'||sign=='-')&&i=='i'));c.real=a;c.imag=(sign=='+')?b:-b;return input;}Complex Complex::operator-(){return(-*this);}Complex Complex::operator+(const Complex &c2){Complex a;a.real=real+c2.real;a.imag=imag+c2.imag;return a;}Complex Complex::operator-(const Complex &c2){Complex a;a.real=real-c2.real;a.imag=imag-c2.imag;return a;}Complex Complex::operator*(const Complex &c2){Complex a;a.real=real*c2.real;a.imag=imag*c2.imag;return a;}Complex Complex::operator/(const Complex &c2){Complex a;a.real=real/c2.real;a.imag=imag/c2.imag;return a;}void Complex::display(){cout<<"("<<real<<","<<imag<<"i)"<<endl;}//下面定义用于测试的main()函数int main(){Complex c1,c2,c3;cout<<"c1: "<<endl;;cin>>c1;cout<<"c2: "<<endl;cin>>c2;cout<<"c1="<<c1<<endl;cout<<"c2="<<c2<<endl;c3=c1+c2;cout<<"c1+c2="<<c3<<endl;c3=c1-c2;cout<<"c1-c2="<<c3<<endl;c3=c1*c2;cout<<"c1*c2="<<c3<<endl;c3=c1/c2;cout<<"c1/c2="<<c3<<endl;return 0;}运行结果：
你可以很有个性，但某些时候请收敛。
