СПРИНТ № 4 | Перегрузка операторов | Урок 3: Перегрузка арифметических операций

#include <numeric>
#include <iostream>

using namespace std;

class Rational {
public:
    Rational() = default;

    Rational(int numerator)
        : numerator_(numerator)
        , denominator_(1) {
    }

    Rational(int numerator, int denominator)
        : numerator_(numerator)
        , denominator_(denominator) {
        Normalize();
    }

    int Numerator() const {
        return numerator_;
    }

    int Denominator() const {
        return denominator_;
    }

    friend std::ostream& operator<<(std::ostream& os, Rational& rat);
    friend std::istream& operator>>(std::istream& in, Rational& rat);
    friend Rational operator+(Rational& left, Rational& right);
    friend Rational operator-(Rational& left, Rational& right);
    friend Rational operator+(Rational& left);
    friend Rational operator-(Rational& left);



private:
    void Normalize() {
        if (denominator_ < 0) {
            numerator_ = -numerator_;
            denominator_ = -denominator_;
        }
        const int divisor = gcd(numerator_, denominator_);
        numerator_ /= divisor;
        denominator_ /= divisor;
    }

    int numerator_ = 0;
    int denominator_ = 1;
};

std::ostream& operator<<(std::ostream& os, const Rational& rat){
    os << rat.Numerator() << "/" << rat.Denominator();
    return os;
}

std::istream& operator>>(std::istream& is, Rational& rat){
    char b;
    is >> rat.numerator_ >> b >> rat.denominator_;
    return is;
}

Rational operator+(Rational& left, Rational& right){
    const int numerator = left.Numerator() * right.Denominator() + right.Numerator() * left.Denominator();
    const int denominator = left.Denominator() * right.Denominator();
    return { numerator, denominator };
}

Rational operator-(Rational& left, Rational& right){
    const int numerator = left.Numerator() * right.Denominator() - right.Numerator() * left.Denominator();
    const int denominator = left.Denominator() * right.Denominator();
    return { numerator, denominator };
}

Rational operator+(Rational& left){
    return {left.numerator_, left.denominator_};
}

Rational operator-(Rational& left){
    return {-left.numerator_, left.denominator_};
}

int main(){
    return 0;
}