duotai

代码说明：

说明：   试写出所能想到的所有形状(包括二维的和三维的)，并生成一个形状层次结构。生成的层次结构要以Shape作为基类，并由此派生出类TwoDimensionalShapeThreeDimensionalShape。开发出层次结构后，定义其中的每一个类。(Write down all the shapes can think of (including the two-dimensional and three-dimensional), and generates a shape hierarchy. Hierarchy to be generated to Shape as the base class and derives class TwoDimensionalShapeThreeDimensionalShape. Developed a hierarchy, the definition of each of these categories.)