Shape成为一个包含接口(供层次结构中的类使用)的抽象基类。从类Shape派生出二维形状类TwoDimensionalShape和三维形状类ThreeDimensionalShape，它们也都是抽象类，然后用虚函数print输出每个类的类型和维数。为了计算类层次结构中每个具体类的对象，这两个类中还要包括虚函数area和volume。最后再编写一个程序测试类Shape的层次结构-Shape into a contained interface (for the class hierarchy to use) an abstract base class. Derived from the class of two-dimensional shape of class Shape and three-dimensional shape of class TwoDimensionalShape ThreeDimensionalShape, they are abstract classes, and then use virtual function print the output for each class type and dimension. To calculate the class hierarchy for each specific class of objects, these two classes should also include the virtual function area and volume. Finally, write a program to test class hierarchy Shape