C++ singleton

class Singleton
{
public:
    ~Singleton() {
        std::cout << "destructor called!" << std::endl;
    }
    Singleton(const Singleton&) = delete;
    Singleton& operator=(const Singleton&) = delete;
    static Singleton& get_instance() {
        static Singleton instance;
        return instance;

    }
private:
    Singleton() {
        std::cout << "constructor called!" << std::endl;
    }
};



int main(int argc, char* argv[])
{
    Singleton& instance_1 = Singleton::get_instance();
    Singleton& instance_2 = Singleton::get_instance();


    return 0;
}