c++多态的一个例子

#include<bits/stdc++.h>
using namespace std;
#define vi virtual
class abstractdrink{
    public:
        //煮水 
        vi void Boil() = 0;
        //冲泡
        vi void Brew() = 0;
        //倒入杯中
        vi void Pourincup() = 0;
        //添加辅料
        vi void Addsomething() = 0;
        void makeDrink()
        {
            Boil();
            Brew();
            Pourincup();
            Addsomething();
        } 
};

class Coffee:public abstractdrink{
        void Boil() {
            cout << "煮开水" << endl; 
        }
        //冲泡
         void Brew() {
             cout << "冲泡咖啡" << endl; 
         }
        //倒入杯中
         void Pourincup() {
             cout << "倒入杯中" << endl;
         }
        //添加辅料
         void Addsomething(){
             cout << "添加牛奶和糖" << endl; 
         }
};

class Tea:public abstractdrink{
        void Boil() {
            cout << "煮开水" << endl; 
        }
        //冲泡
         void Brew() {
             cout << "冲泡茶叶" << endl; 
         }
        //倒入杯中
         void Pourincup() {
             cout << "倒入杯中" << endl;
         }
        //添加辅料
         void Addsomething(){
             cout << "添加枸杞" << endl; 
         }
};
void dowork(abstractdrink *abs)
{
    abs->makeDrink();
    delete abs;
}
void test()
{
    dowork(new Coffee);
    cout << "---------->" << endl;
    dowork(new Tea);
} 

int main()
{
    test();
    return 0;
}