Introduction - If you have any usage issues, please Google them yourself
Step1: for the experiment three rectangle defined class derived a subclass: Square classes. Square type of operation is also seeking perimeter and area. Then in addition to this subclass inherited from the parent class methods, but also need to define what methods? Square class lists all domains and methods. Written verification squares programming class. Step2: defines the interface Printable, including a method printItMyWay (), this method does not shape parameter, the return value is null. Step3: rewrite Rectangle class that met Printable interface with printItMyWay () method of the rectangle information (length, width, perimeter, area) printed on the screen. Step4: rewrite the square class, overloading printItMyWay () method, the square side length, perimeter, area printed on the screen. Step5: Finally, rectangles and squares organized into a package MyFigures.