fraction start example

main.cpp

#include <iostream>
using namespace std;

class Fraction {
    int numerator;
    int denominator;

    // наибольший общий делитель
    int gcd(int a, int b) {
        while (b != 0) {
            int temp = b;
            b = a % b;
            a = temp;
        }
        return a;
    }

    void reduce() {
        int divisor = gcd(numerator, denominator);
        numerator /= divisor;
        denominator /= divisor;

        if (denominator < 0) {
            numerator = -numerator;
            denominator = -denominator;
        }
    }

public:
    explicit Fraction() : Fraction(0, 1) {}

    explicit Fraction(double decimal) : Fraction() {
        denominator = 1;
        while (decimal != (int)decimal) {
            decimal *= 10;
            denominator *= 10;
        }
        numerator = (int)decimal;
        reduce();
    }

    explicit Fraction(int num, int den) {
        setNumerator(num);
        setDenominator(den);
    }

    void setNumerator(int num) {
        numerator = num;
    }

    void setDenominator(int den) {
        if (den == 0) {
            throw "Знаменатель не может быть нулём.";
        }
        denominator = den;
    }

    int getNumerator() const { return numerator; }

    int getDenominator() const { return denominator; }

    void display() const {
        cout << numerator << "/" << denominator << "\n";
    }

    double toDouble() const {
        return (double)(numerator) / denominator;
    }

    Fraction add(const Fraction& other) const {
        return Fraction(numerator * other.denominator + other.numerator * denominator,
            denominator * other.denominator);
    }

    Fraction subtract(const Fraction& other) const {
        return Fraction(numerator * other.denominator - other.numerator * denominator,
            denominator * other.denominator);
    }

    Fraction multiply(const Fraction& other) const {
        return Fraction(numerator * other.numerator, denominator * other.denominator);
    }

    Fraction divide(const Fraction& other) const {
        if (other.numerator == 0) {
            throw invalid_argument("Делить на ноль нельзя.");
        }
        return Fraction(numerator * other.denominator, denominator * other.numerator);
    }

    bool equals(const Fraction& other) const {
        return numerator == other.numerator && denominator == other.denominator;
    }

    bool notEquals(const Fraction& other) const {
        return !equals(other);
    }
};

int main() {
    setlocale(0, "");

    Fraction frac1(3, 4);
    Fraction frac2(2, 5);

    frac1.display();
    frac2.display();

    Fraction sum = frac1.add(frac2);
    cout << "Сумма: ";
    sum.display();

    Fraction difference = frac1.subtract(frac2);
    cout << "Разность: ";
    difference.display();

    Fraction product = frac1.multiply(frac2);
    cout << "Произведение: ";
    product.display();

    Fraction quotient = frac1.divide(frac2);
    cout << "Частное: ";
    quotient.display();

    cout << "Десятичное значение " << frac1.getNumerator() << "/" << frac1.getDenominator() << " = " << frac1.toDouble() << "\n";
}