class Rational{public:    const Rational operator*( const Rational& rhs);    Rational(int num);private:    int a;};Rational::Rational(int num) :a(num){}const Rational Rational::operator*(const Rational& rhs){    return Rational(this->a * rhs.a);}int main(){    Rational a(2);    Rational b(3);    Rational c = a * b;    return 0;}