观察者Observer模式C++实现

Observer C++实现#include<string>

#include<iostream>

#include<set>



classIObserver;



classISubject

{

public:

virtualvoidregisterObserver(IObservero)=0;

virtualvoidremoveObserver(IObservero)=0;

virtualvoidnotifyObservers()=0;

};





classIObserver

{

protected:

IObserver(){};

public:

virtualvoidupdate(floattemp,floathumidity,floatpressure)=0;



};



classIDisplayElement

{

protected:

IDisplayElement(){};

public:

virtualvoiddisplay()=0;

};





typedef std::set<IObserver>ObserverList;

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



classWeatherData:publicISubject

{

private:

ObserverList m_Oberservers;

floatm_temp;

floatm_humidity;

floatm_pressure;



public:

WeatherData () {};

~WeatherData () {};

virtualvoidregisterObserver(IObservero)

{

m_Oberservers.insert(o);

}

virtualvoidremoveObserver(IObservero)

{

ObserverListIter iter=m_Oberservers.find(o);

if(iter!=m_Oberservers.end())

{

m_Oberservers.erase(iter);

}

}

virtualvoidnotifyObservers()

{

ObserverListIter iter=m_Oberservers.begin();

for(;iter!=m_Oberservers.end();iter++)

{

//notify All Observers

IObserverpObserver=static_cast<IObserver>(iter);

pObserver->update(m_temp,m_humidity,m_pressure);

}

}

voidmeasurementsChanged()

{

notifyObservers();

}



voidsetMeasurements(floattemp,floathumidity,floatpressure)

{

m_temp=temp;

m_humidity=humidity;

m_pressure=pressure;

measurementsChanged();

}



};





classCurrentConditionsDisplay:publicIObserver,publicIDisplayElement

{

floatm_temp;

floatm_humidity;

ISubjectm_WeatherData;



public:



virtualvoidupdate(floattemp,floathumidity,floatpressure)

{

m_temp=temp;

m_humidity=humidity;

display();

}



virtualvoiddisplay()

{

std::cout<<"Current Conditions:"<<m_temp<<","

<<m_humidity<<std::endl;

}



};







classCurrentConditionsDisplay2:publicIObserver,publicIDisplayElement

{

floatm_temp;

floatm_humidity;

floatm_pressure;



public:





virtualvoidupdate(floattemp,floathumidity,floatpressure)

{

m_temp=temp;

m_humidity=humidity;

m_pressure=pressure;

display();

}



virtualvoiddisplay()

{

std::cout<<"Current Conditions2:"<<m_temp<<","

<<m_humidity<<","<<m_pressure<<std::endl;

}



};







intmain()

{

CurrentConditionsDisplaydisplay1=newCurrentConditionsDisplay();

CurrentConditionsDisplay2display2=newCurrentConditionsDisplay2();



WeatherData*data=newWeatherData();

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();



return0;

}

原文链接: https://www.cnblogs.com/mumuliang/archive/2010/11/24/1886243.html

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