请编写程序，处理一个复数与一个double数相加的运算，结果存放在一个double型的变量d1中，输出d1的值，再以复数形式输出此值。定义Complex(复数)类，在成员函数中包含重载类型转换运算符:
operator double() { return real; }

一个复数与一个double数

d1的值和复数形式的此值

3 42.5

d1=5.50c2=(5.50, 0.00)

/* C++代码 */#include <iostream>#include <iomanip>using namespace std;class Complex{public:    Complex();    Complex(double r);    Complex(double r,double i);    operator double();    void display();private:    double real;    double imag;};Complex::Complex(){return ;}Complex::Complex(double r){real=r;imag=0;}Complex:: Complex(double r,double i){real=r;imag=i;}Complex::operator double(){return real; }void Complex::display()  {   cout<<"("<<real<<", "<<imag<<")"<<endl;}  int main(){    cout<<setiosflags(ios::fixed);   cout<<setprecision(2);    double real,imag;    cin>>real>>imag;    Complex c1(real,imag);    double d1;    cin>>d1;    d1=d1+c1;    cout<<"d1="<<d1<<endl;    Complex c2=Complex(d1);    cout<<"c2=";    c2.display();    return 0;}