观察者Observer模式C++实现

#include <string>
#include <iostream>
#include <set>

class IObserver;

class ISubject
{
public:
    virtual void registerObserver(IObserver * o) = 0;
    virtual void removeObserver(IObserver * o) = 0;
    virtual void notifyObservers() = 0;
};


class IObserver
{
protected:
    IObserver(){};
public:
    virtual void update(float temp, float humidity, float pressure) = 0;

};

class IDisplayElement
{
protected:
    IDisplayElement(){};
public:
    virtual void display() = 0;
};


typedef std::set<IObserver *> ObserverList;
typedef std::set<IObserver *>::iterator ObserverListIter;

class WeatherData: public ISubject
{
private:
    ObserverList m_Oberservers;
    float m_temp;
    float m_humidity;
    float m_pressure;

public:
    WeatherData () {};
    ~WeatherData () {};
    virtual void registerObserver(IObserver * o)
    {
        m_Oberservers.insert(o);
    }
    virtual void removeObserver(IObserver * o)
    {
        ObserverListIter iter = m_Oberservers.find(o);
        if (iter!=m_Oberservers.end())
        {
            m_Oberservers.erase(iter);
        }
    }
    virtual void notifyObservers()
    {
        ObserverListIter iter = m_Oberservers.begin();
        for (;iter!=m_Oberservers.end();iter ++ )
        {
            // notify All Observers
            IObserver * pObserver = static_cast<IObserver *>(* iter);
            pObserver->update(m_temp,m_humidity,m_pressure);
        }
    }
    void measurementsChanged()
    {
        notifyObservers();
    }

    void setMeasurements(float temp, float humidity, float pressure)
    {
        m_temp = temp;
        m_humidity = humidity;
        m_pressure = pressure;
        measurementsChanged();
    }

};


class CurrentConditionsDisplay:public IObserver,public IDisplayElement
{
    float m_temp;
    float m_humidity;
    ISubject *m_WeatherData;

public:

    virtual void update(float temp, float humidity, float pressure) 
    {
        m_temp = temp;
        m_humidity = humidity;
        display();
    }

    virtual void display()
    {
        std::cout << "Current Conditions:" << m_temp << ","
            << m_humidity <<std::endl;
    }
    
};



class CurrentConditionsDisplay2:public IObserver,public IDisplayElement
{
    float m_temp;
    float m_humidity;
    float m_pressure;

public:


    virtual void update(float temp, float humidity, float pressure) 
    {
        m_temp = temp;
        m_humidity = humidity;
        m_pressure = pressure;
        display();
    }

    virtual void display()
    {
        std::cout << "Current Conditions2:" << m_temp << ","
            << m_humidity << "," << m_pressure <<std::endl;
    }

};



int main()
{
    CurrentConditionsDisplay * display1 = new CurrentConditionsDisplay();
    CurrentConditionsDisplay2 * display2 = new CurrentConditionsDisplay2();

    WeatherData * data = new WeatherData();
    data->registerObserver( display1);
    data->registerObserver (display2);

    data->setMeasurements(100,0,200);
    data->setMeasurements(50,50,500);

    data->removeObserver(display1);

    data->setMeasurements(10,10,10);

    getchar();

    return 0;
}