#include <iostream>

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

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

using namespace std;

int main()
{
  Circle C1;
  Circle C2;

  C1.SetRadius(1);
  C2.SetRadius(10);

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

  C1.SetRadius(2);
  C2.SetRadius(3);

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

  return 0;
}

/*
output:
The area of C1 is 3.14
The area of C2 is 314
The area of C1 is 12.56
The area of C2 is 28.26
*/