#include <iostream> // includes standard input/output functions

using namespace std; // allows access to hidden names like cout, cin

//Declaration
class Circle  
{
public:
  Circle();
  Circle(double r);
  void SetRadius(double r);  // sets member variable radius to r
  double AreaOf();           // returns area of circle as a double
private:
  double radius;             // radius of circle
};

//Definition (Implementation):

Circle::Circle()
{
  double r;
  cout<<"New Circle!! Enter the radius:";
  cin>>r;
  radius = r;
}

Circle::Circle(double r)
{
  radius = r;
}

void Circle::SetRadius(double r)
{
  radius = r; //radius refers to this object’s Circle::radius
}

double Circle::AreaOf()
{
  return (3.14*radius*radius);
}

int main()
{
  Circle C1; // calls default constructor
  Circle C2(10); // calls constructor with one (double) parameter

  cout<<"The area of C1 is "<<C1.AreaOf()<<endl;
  cout<<"The area of C2 is "<<C2.AreaOf()<<endl;

  return 0;
}