Re: Singleton --- Just Look and give Suggestion's

1. its not executing display() properly ....just look to it
2. Suggest effective way to write MUTEX class at User level

#include <iostream.h>

using namespace std;

template<typename TYPE>
class Singleton
{
  private :
    Singleton() { cout<<" constructor Invoked "<< endl; }
  ~Singleton() { cout<<" Destructor Invoked "<<endl; }
    Singleton(const Singleton<TYPE> & a)
         { cout<<" Copy Constructor Invoked "<<endl; }

   const Singleton<TYPE> & operator = (const Singleton<TYPE> &);

   static TYPE * instance;
   static volatile long Flag; // Flag is volatile.

  public :
   static TYPE * GetInstance( void )
    {
        if( Flag == 0 )
          {
              // TO BE DONE Guard<Mutex> acquire();
                if( Flag == 0 )
                   {
                           if( instance != NULL)
                            { try
                                   { instance = new TYPE();}
                               catch(...)
                                   { cout <<"Creation of Object failed
"<<endl; }

                            }
                     cout<<" Instance Created Successfully \n";

                     Flag = 1;
             // Mutex.release();
          }
        return instance;
        }
    else
        {
           cout<<" Returning the Already Created Instance \n";
           return instance;
        }
    }
};

template<typename TYPE>
TYPE * Singleton<TYPE>::instance = 0 ;

template<typename TYPE>
volatile long Singleton<TYPE>::Flag = 0;

class A
{
  public :
     int i,j;
     A(int i = 1 , int j = 1):i(i),j(i){}

     void display()
     { cout<<" value of i "<< i <<" value of j "<< j <<endl; }
};

int main()
{
   A * obj1 = Singleton<A>::GetInstance();
   A * obj2 = Singleton<A>::GetInstance();
   A * obj3 = Singleton<A>::GetInstance();

   obj1->display();
  //obj2->display();
  //obj3->display();

  // To check if it call destructor of Object
   delete obj1;
   delete obj2;
   delete obj3;
}