p335重载流提取运算符.cpp

谭浩强 《C++ 程序设计》第三版的部分课后练习题源码

#include<iostream>
using namespace std;
class Complex
{
      public:
      Complex(int a=0,int b=0):real(a),imag(b){}
      Complex operator+(Complex &a);
      friend ostream & operator <<(ostream &output,Complex &a);
      friend istream & operator >>(istream &input,Complex &a); 
      private:
              int real;
              int imag;
};

ostream & operator <<(ostream &output,Complex &a)
{    if(a.imag>0)  cout<<a.real<<"+"<<a.imag<<"i"<<endl;
     else if(a.imag<0)  cout<<a.real<<a.imag<<"i"<<endl;
     else cout<<a.real<<endl;
     return output;
}

istream & operator >>(istream &input,Complex &a)
{    
     cout<<"please input the real part and the imag part: ";
     cin>>a.real>>a.imag;
     return input;
}


Complex Complex::operator+(Complex &a)
{
        return(Complex(a.real+real,a.imag+imag));
}

int main()
{
    Complex c1,c2,c3;
    cin>>c1>>c2;
    cout<<c1<<endl;
    cout<<c2<<endl;
    c3=c1+c2;
    cout<<"c3=c1+c2"<<endl;
    cout<<c3;
    system("pause");
    return 0;
    }