运用面向对象方法设计圆类和圆柱体类并建立继承关系，并为有关

类设计构造函数、析构函数、成员数据设置/提取操作、面积/体积计算函数。在

主函数中，分别创建一个圆类对象和圆柱体类对象，调用和执行相关成员函数，

观察并分析程序运行结果-Circle design using object-oriented approach and the establishment of classes and class inheritance relationship cylinder and is designed for class constructors, destructors, member data set/extraction operation, area/volume calculation function. In the main function, namely to create a circular cylinder class object and class object member function invocation and execution related to observe and analyze the result of the program