singletop class in c++

general
1

wap to implement singleton class in c++??

2

Here goes a simple implementation.

#include <iostream>
    using namespace std;
    class Singleton {
    private:
        int i;
        Singleton() {
            cout<<"Constructing"<<endl;
        }
        static Singleton* instance;
    public:
        static Singleton* getInstance() {
            if (instance == NULL) {
                instance = new Singleton();
            }
            return instance;
        }
        void set(int j) {
            i = j;
        }
        int get() {
            return i;
        }
        void incr() {
            i++;
        }
    
        ~Singleton() {
            cout<<"Destructing"<<endl;
        }
    
    };
    
    Singleton* Singleton::instance = NULL;
    
    int main()
    {
        Singleton *x = Singleton::getInstance();
        x->set(5);
        x->incr();
        Singleton *y = Singleton::getInstance();
        cout<<"Result: "<<y->get()<<endl;
    
    }