class_constructors.cpp

  #include <iostream>
using namespace std;
#define PI 3.142

class circle{

private:
	double radius;

public:
	circle();
	circle(double);
	~circle();
	void setRadius(double);
	double getRadius() const{
		return radius;
	}
	double getArea() const{
		return PI*radius*radius;
	}
	double getPerimeter() const{
		return 2*PI*radius;
	}

};
circle::circle(){
	radius = 0;
}

circle::circle(double r){
	radius = r;
}
circle::~circle(){
	cout << "calling destructor" << endl;
}

int main(){

	circle c1;
	cout << c1.getRadius() << endl;
	circle c2(3.3);
	cout << c2.getRadius() << endl;

	return 0;

}