#include<iostream>
using namespace std;
class geometricobject { //baseclass
	public:
		virtual void geo( ) {
			cout << "Just a geometric object" << endl;
		}
};
class rectangle : public geometricobject { //derived class
	public:
		virtual void geo( ) {
			cout << "I'm a rectangle" << endl;
		}
};
class circle : public geometricobject { // derived class
	public:
		virtual void geo( ) {
			cout << "I'm a circle" << endl;
		}
};

int main( ) {
	geometricobject *ptr; //pointer to base class
	int which, rerun=1;
	while(rerun==1) {

		do {
			cout << "Enter:\n\t"
			     <<"1 for geometricobject\n\t"
			     <<"2 for rectangle\n\t"
			     <<"3 for circle\n\t"
			     <<"4 to quit"<<endl;
			cin >> which;
			
		} while (which < 1 || which > 4);
		switch (which) { //set pointer depending on user choice
			case 1:
				ptr = new geometricobject;
				break;
			case 2:
				ptr = new rectangle;
				break;
			case 3:
				ptr = new circle;
				break;
			case 4:
				rerun=0;
				break;
		}

		if (rerun==0) break;

		ptr -> geo( ); //run-time binding
		delete ptr; //don’t leave junk hanging around
	}
	return 0;
}