singleton class

[ranjitkumar]

What is a singleton class???
What is its use???

[r035198x]

What is a singleton class???
What is its use???

A class whose design is such that it can only be instantiated once. This means only one instance of it can exist e.g Application classes maybe singleton classes

[vermarajeev]

And it could look something like this

class SingleTon
{
public:
    static SingleTon* instance();
private:
    SingleTon(){};
    SingleTon( const SingleTon& );
    SingleTon& operator == ( const SingleTon& );
    static SingleTon* pinstance;
};
SingleTon* SingleTon::pinstance = 0;
 
SingleTon* SingleTon::instance()
{
    if(pinstance == 0)
    {
        pinstance = new SingleTon;        
    }
    return pinstance;
}
 
int main(int argc, char** argv[])
{
 
    SingleTon* p1 = SingleTon::instance();
    SingleTon* p2 = p1->instance();
    return 0;
}