Fraction Operations

class Fraction {
    int uppernum;
    int lowernum;
public:
    Fraction(int m_uppernum, int m_lowernum) {
        this->uppernum = uppernum;
        this->lowernum = lowernum;
    }
    void showdata() {
        cout << uppernum << "/" << lowernum << endl;
    }
    friend Fraction operator*(Fraction& f1, Fraction& f2);
    friend Fraction operator/(Fraction& f1, Fraction& f2);
    friend Fraction operator*(Fraction& f1, int a);
    friend Fraction operator*(int a,Fraction& f1);
    friend Fraction operator/(Fraction& f1, int a);
    friend Fraction operator/(int a, Fraction& f1);
};
Fraction operator*(Fraction& f1, Fraction& f2)
{
    return Fraction(f1.uppernum * f2.uppernum, f1.lowernum * f2.lowernum);
}
Fraction operator/(Fraction& f1, Fraction& f2) {
    return Fraction(f1.uppernum * f2.lowernum, f1.lowernum * f2.uppernum);
}
Fraction operator*(Fraction& f1, int a)
{
    return Fraction(f1.uppernum * a, f1.lowernum * 1);
}
Fraction operator*(int a, Fraction& f1) {
    return Fraction(f1.uppernum * a, f1.lowernum * 1);
}
Fraction operator/(Fraction& f1, int a) {
    return Fraction(f1.uppernum * 1, f1.lowernum * a);
}
Fraction operator/(int a, Fraction& f1) {
    return Fraction(f1.lowernum * 1, f1.uppernum * a);
}
int main()
{
    setlocale(LC_ALL, "rus");

    Fraction f1(1, 2);
    Fraction f2(1, 4);
    Fraction f3 = f1 * 4;
    Fraction f4 = 4 * f1;
    Fraction f5 = f1 / f2;
    Fraction f6 = f1 / 2;
    Fraction f7 = 2 / f1;
    return 0;
}