singleton_object.cpp

#include <iostream>
#include <string>
using namespace std;

class Car
{
	static Car* single_instance_declared;
	string _name;
	string _engine;
	int _wheels;
	bool _kers; // KERS

	// denying initializing through constructor
	Car(const Car&);
	Car& operator=(const Car&);
	Car();

public:
	static Car* getInstance();
	void set_kers(bool);
	bool kers();
};

Car* Car::single_instance_declared=nullptr;

Car::Car()
{
	_name = "Ferrari f14T";
	_engine = "Ferrari v6 turbo";
	_wheels = 4;
	_kers = false;	
}

void Car::set_kers(bool status)
{
	this-> _kers = status;
}

bool Car::kers()
{
	return this-> _kers;
}

Car* Car::getInstance()
{
	if (!single_instance_declared)
	{
		single_instance_declared = new Car();
		return single_instance_declared;
	}
	return single_instance_declared;
}

int main(int argc, const char *argv[])
{
	Car* ferrari_f1 = Car::getInstance();
	Car* fake_ferrari = Car::getInstance();

	ferrari_f1-> set_kers(true);

	cout << fake_ferrari-> kers() << endl;
}