#include <iostream>
#include<math.h>
using namespace std;
class Fraction 
{
private:
    int tu;
    int mau;
public:
    // 2. Default constructor
    Fraction() 
    {
        tu = 0;
        mau = 1;
    }
    // 3. Parameterized constructor
    Fraction(int num, int den) {
        tu = num;
        mau = (den == 0) ? 1 : den;  // Tránh chia cho 0
    }

    // 4. Copy constructor
    Fraction(const Fraction &other) 
    {
        tu = other.tu;
        mau = other.mau;
    }

    // 5. Overload input operator >>
    friend istream& operator>>(istream& is, Fraction& f) {
        cout << "Enter tu: ";
        is >> f.tu;
        cout << "Enter mau (? 0): ";
        is >> f.mau;
        if (f.mau == 0) {
            cout << "Invalid mau. Reset to 1.\n";
            f.mau = 1;
        }
        reduceFraction(f);
        return is;
    }

    // 6. Overload output operator <<
    friend ostream& operator<<(ostream& os, const Fraction& f) {
        os << f.tu << "/" << f.mau;
        return os;
    }

    // 7. Overload + operator
    Fraction operator+(const Fraction& other) {
        Fraction result;
        result.tu = tu * other.mau + other.tu * mau;
        result.mau = mau * other.mau;
        reduceFraction(result);
        return result;
    }

    // 8. Overload / operator
    Fraction operator/(const Fraction& other) {
        Fraction result;
        result.tu = tu * other.mau;
        result.mau = mau * other.tu;
        if (result.mau == 0) {
            cout << "Division by zero. Reset result to 0/1.\n";
            result.tu = 0;
            result.mau = 1;
        }
        reduceFraction(result);
        return result;
    }

    // 9. Overload == operator (returns -1, 0, 1)
    int operator==(const Fraction& other) const 
    {
        int lhs = tu * other.mau;
        int rhs = other.tu * mau;
        if (lhs < rhs) return -1;
        else if (lhs > rhs) return 1;
        else return 0;
    }

    // 10. Friend function to reduce fraction
    friend void reduceFraction(Fraction &f);
};

// Helper: Tìm U?c chung l?n nh?t (GCD)
int gcd(int a, int b) {
    while (b != 0) {
        int r = a % b;
        a = b;
        b = r;
    }
    return a;
}

// 10. Friend function to reduce a fraction
void reduceFraction(Fraction &f) 
{
    if (f.tu == 0) 
    {
        f.mau = 1;
        return;
    }

    int g = gcd(abs(f.tu), abs(f.mau));
    f.tu /= g;
    f.mau /= g;

    // Ðua d?u âm v? t? s?
    if (f.mau < 0) {
        f.tu *= -1;
        f.tu *= -1;
    }
}
int main() {
    Fraction f1, f2;

    // Nh?p hai phân s?
    cout << "Enter first fraction:\n";
    cin >> f1;

    cout << "Enter second fraction:\n";
    cin >> f2;

    // In ra hai phân s?
    cout << "\nFraction 1: " << f1 << endl;
    cout << "Fraction 2: " << f2 << endl;

    // C?ng hai phân s?
    Fraction sum = f1 + f2;
    cout << "\nSum: " << sum << endl;

    // Chia hai phân s?
    Fraction result = f1 / f2;
    cout << "Division result: " << result << endl;

    // So sánh hai phân s?
    int comparison = f1 == f2;
    if (comparison == 0) {
        cout << "The two fractions are equal.\n";
    } else if (comparison < 0) {
        cout << "Fraction 1 is smaller than Fraction 2.\n";
    } else {
        cout << "Fraction 1 is greater than Fraction 2.\n";
    }

    return 0;
}

Trương Đình Huy