Chapter 15, Problem 6PP

Flesh out Programming Project 5. Give new definitions for the various constructors and the member functions Figure::center, Figure::draw, Figure::erase, Triangle::draw, Triangle::erase, Rectangle::draw, and Rectangle::erase so that the draw functions actually draw figures on the screen by placing the character '*' at suitable locations. For the erase functions, you can simply clear the screen (by outputting blank lines or by doing something more sophisticated). There are a lot of details in this problem, and you will have to make decisions about some of them on your own.