[创建型模式] Singleton

Singleton.h

//

//  Singleton.h

//  Singleton

//

//  Created by Cheney Shen on 11-2-20.

//  Copyright 2011年 __MyCompanyName__. All rights reserved.

//



#ifndef _SINGLETON_H_

#define _SINGLETON_H_



#include <iostream>

using namespace std;



class Singleton

{

    public:

    static Singleton* Instance();

    

    protected:

    Singleton();

    

    private:

    static Singleton* _instance;

    

};



#endif  //~_SINGLETON_H_

Singleton.cpp

//

//  Singleton.cpp

//  Singleton

//

//  Created by Cheney Shen on 11-2-20.

//  Copyright 2011年 __MyCompanyName__. All rights reserved.

//



#include "Singleton.h"



#include <iostream>

using namespace std;



Singleton* Singleton::_instance = 0;



Singleton::Singleton()

{

    cout<<"Singleton..."<<endl;

}



Singleton* Singleton::Instance()

{

    if(_instance==0){

        _instance = new Singleton();

    }

    

    return _instance;

}

main.cpp

//

//  main.cpp

//  Singleton

//

//  Created by Cheney Shen on 11-2-20.

//  Copyright 2011年 __MyCompanyName__. All rights reserved.

//

#include "Singleton.h"



#include <iostream>

using namespace std;



int main (int argc, const char * argv[]) {



    Singleton* sgn = Singleton::Instance();

    

    return 0;

}