定义必要的成员函数，以便能输出book类对象的name和pagecount的值。编写一个主函数测试你的程序。注意派生方式设定为共有派生。-Define a necessary member functions, in order to output the object of the book class name and the pagecount the value. Write a main function to test your program. Note that the derived set for the total derived.