定义一个抽象类Shape代表一个形状类，具有一个计算形状的面积的抽象方法，一个具有计算形状的周长的抽象方法。定义一个Shape类的子类Circle类表示一个圆，，此类具有一个表示半径的成员变量，实现这个类，定义一个单独的类测试此类。定义一个Shape类的子类Retangle类表示一个矩形，，此类具有表示高和宽的成员变量，实现这个类，定义一个单独的类测试此类-Define an abstract class Shape represents a shape class, with a calculation of the shape of the area of ​ ​ abstract methods, an abstract method to calculate the shape of the perimeter. Definition of a Shape class, subclass Circle class represents a circle, such a member variable of radius, this class, define a separate class test such. Define a Shape subclass Retangle class represents a rectangle, such has said the height and width member variables of this class, define a separate class test such