模板方法模式

#ifndef CAFFEINEBEVERAGE_H
#define CAFFEINEBEVERAGE_H

#include <iostream>

using namespace std;

class CaffeineBeverage
{
public:
    void prepareRecipe()
    {
        boilWater();
        brew();
        pourInCup();
        if (customerWantsCondiments())
        {
            addCondiments();
        }        
    }
    virtual void brew() = 0;
    virtual void addCondiments() = 0;
    void boilWater()
    {
        cout<<"Boiling water"<<endl;
    }
    void pourInCup()
    {
        cout<<"Pouring into cup"<<endl;
    }
    //可以对Hook使用策略模式优化。
    virtual bool customerWantsCondiments()
    {
        return true;
    }
};

#endif

#ifndef TEA_H
#define TEA_H

#include "CaffeineBeverage.h"
#include <iostream>

using namespace std;

class Tea : public CaffeineBeverage
{
public:
    void brew()
    {
        cout<<"Steeping the tea"<<endl;
    }
    void addCondiments()
    {
        cout<<"Adding Lemon"<<endl;
    }
};

#endif

#ifndef COFFEE_H
#define COFFEE_H

#include "CaffeineBeverage.h"
#include <iostream>
#include <string>

using namespace std;

class Coffee : public CaffeineBeverage
{
public:
    void brew()
    {
        cout<<"Dripping Coffee through filter"<<endl;
    }
    void addCondiments()
    {
        cout<<"Adding Sugar and Milk"<<endl;
    }
    bool customerWantsCondiments()
    {
        string answer = string("");
        cout<<"Would you like milk and sugar with your coffee (y/n)?"<<endl;
        cin>>answer;
        if (answer == string("y"))
        {
            return true;
        }
        else
        {
            return false;
        }
    }
};

#endif

#include "CaffeineBeverage.h"
#include "Coffee.h"
#include "Tea.h"

int main()
{
    Tea* tea = new Tea;
    tea->prepareRecipe();
    Coffee* coffee = new Coffee;
    coffee->prepareRecipe();
    return 0;
}