(1). 编写程序定义基类Animal，成员变量age为私有的，构造派生类dog，在其成员函数SetAge（int n）中直接对age赋值时会出现什么问题？把age变为公有的呢？

(2).定义一个基类BaseClass，有整形变量Number，构造其派生类DerivedClass，观察构造函数和析构函数的执行情况.

(3). 编写一个车（vehicle）基类，由此派生出自行车（bicycle）类和汽车（motorcar）类，注意把vehicle派生成虚基类，再从bicycle和 motorcar中派生出摩托车（torcycle）类，在ｍａｉｎ（）函数中调试。

-(1). Write a program defines the base class Animal, as the private member variables age, structure derived class dog, in its member functions SetAge (int n) in the direct assignment of the age when what problems will arise? To age into a publicly owned it?(2). Define a base class BaseClass, there is integer variable Number, construct its derived classes DerivedClass, observe the constructor and destructor implementation.(3). To prepare a car (vehicle) base class, thus derived a bike (bicycle) classes and cars (motorcar) class, pay attention to vehicle were generated virtual base class, and then derived from the bicycle and motorcar out of motorcycle (torcycle ) class, in the main () function to debug.