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(2,0),c2; double d1; d1=2.5+c1; cout<<"d1="<<d1<<endl; c2=Complex(d1); cout<<"c2="; c2.display(); return 0;}