Develop the Shape application such that:

Rectangle, Ellipse, and Triangle classes inherit from the Shape class.

Develop the Square and Circle class where Square inherits from Rectangle and Circle inherits from Ellipse. Triangle has no derived class.

For each class, implement the overridden methods draw, move, and erase. Each method should only have an output statement such as Rectangle draw method that will be displayed when the method is invoked.

Implement the default constructors for each class with a corresponding message to be displayed when invoked. No initializations are required; that is, the output message will be the only executable statement in the constructors.

Do not implement any other methods for these classes ( i.e., toString, equals, getters and setters ).

Implement a ShapeTest class which will instantiate an object of each class. Exercise each of the draw, move, and erase methods of each class

Remember to make sure that there is only a single class per file.

I don't know how to start

what does single class per file mean??