Singleton class - only a single object

make a class in c++ such that we can make only one instance of the class ( we can make only a single object )

-contributed by rohit

possible solution:
class
{
int a;
}obj1;

your solution is wrong we can create second object also by giving its name there
your solution should be such that if someone tries to declare another instance of this class then that should give an error message

how about using some static counter...and checking in constructor itself?
please put the ans,if u know.

yes u are right we have to use either static variable inside class or a global variable

first try to make a object of a class which has default constructor as private and no constructor as public

#include<iostream>
using namespace std;
class a
{

a(){//some code
}
a(a &);
public:
static a dube;
}
a::dube;
main()
{

cout<<"hahahha";
}

yes this will create a single object but the object is created inside class and cannot be used in main without scope resolution operator along with object.
there exist another solution also

waise kaun ho bhai obama bahut tagda solution tha yaar ye

class sample
{
static sample *ptr ;
private:
sample( )
{
}
public:
static sample* create( )
{
if ( ptr == NULL )
ptr = new sample ;
return ptr ;
}
} ;
sample *sample::ptr = NULL ;
void main( )
{
sample *a = sample::create( ) ;
sample *b = sample::create( ) ;
}

are rohit bhai aapka solution kabhi galat ho sakta hai