第六题

#include <iostream> using namespace std; class Complex  {public:    Complex(){real=0;imag=0;}    Complex(double r){real=r;imag=0;}    Complex(double r,double i){real=r;imag=i;}    operator double(){return real;}    void display();   private:    double real;    double imag;  };     void Complex::display() {cout<<"("<<real<<", "<<imag<<")"<<endl;}  int main() {Complex c1(3,4),c2;  double d1;  d1=2.5+c1;  cout<<"d1="<<d1<<endl;  c2=Complex(d1);  cout<<"c2=";  c2.display();  return 0; }