class mSingleObj {
private:
    static shared_ptr<mSingleObj> instance;
    string description = "this is single instance object";
    // private constructor so that we can not create an instance
    mSingleObj(){}
    // private copy constructor and assignment operator
    //  previous version of c++
    mSingleObj(const mSingleObj&){}
    mSingleObj& operator=(const mSingleObj&) {}
    // move constructor and move assignment operator
    // >= c++11 we can delete
    mSingleObj(mSingleObj&& ) = delete;
    mSingleObj& operator=(mSingleObj&& ) = delete;
public:
    //the only one way to to get object
    static shared_ptr<mSingleObj> getInstance() {
        return instance;
    }
    void display() {
        cout << description << endl;
    }
    ~mSingleObj() { cout << "Destructor called only one..." << endl; }
};
//static object need to be initialized outside the class defination
shared_ptr<mSingleObj> mSingleObj::instance(new mSingleObj());

void testSingletonObj() {    
    shared_ptr<mSingleObj> sObj = mSingleObj::getInstance();
    sObj->display();
    shared_ptr<mSingleObj> other_sObj = mSingleObj::getInstance();
    other_sObj->display();
    //check whether objects are the same
    cout << "(sObj) Address of managed object: " << sObj.get() << std::endl;
    cout << "(other_sObj) Address of managed object: " << other_sObj.get() << std::endl;
}