// main.cpp
#include <iostream>
#include "Rational.h"

using namespace std;

int main()
{
    Rational r2(2, 11), r3(1, -3), r5(18, 6);
    Rational res1 = 3 + r2 * r3;
    Rational res2 = (3 + r2) * r3;
    Rational res3 = 3 + r3 * (r2 + 2) / (r5 - r3);

    cout << 3 << " + " << r2 << " * " <<  r3 << " = " << res1 << endl;
    cout << "(" << 3 << " + " << r2 << ")" << " * " <<  r3 << " = " << res2 << endl;
    cout << 3 << " + " << r3 << " * " << "(" << r2 << " + " << 2 << ")" << "/"
         << "(" << r5 << " - " << r3 << ")" << " = " << res3 << endl;

    return 0;
}

// Rational.h
#ifndef RATIONAL_H
#define RATIONAL_H

#include <iostream>

using namespace std;

class Rational
{
public:
   Rational(int numerator);
   Rational(int numerator, int denominator);
   ~Rational() {}
   Rational(const Rational& copy);

   Rational& operator=(const Rational& other);
   Rational& operator=(int i);

   int numerator() const { return numer; }
   int denominator() const { return denom; }

   Rational operator++() const;
   Rational operator--() const;

   bool operator==(const Rational& other) const;
   bool operator>=(const Rational& other) const;
   bool operator<=(const Rational& other) const;
   bool operator>(const Rational& other) const;
   bool operator<(const Rational& other) const;

   double value() const;

private:
   int numer;
   int denom;

   void initialize(int numerator, int denominator);

   friend ostream& operator<<(std::ostream &, const Rational &);
   friend istream& operator>>(std::istream &, Rational &);
   friend int nwd(int, int);

   friend Rational operator+(const Rational&, const Rational&);
   friend Rational operator-(const Rational&, const Rational&);
   friend Rational operator*(const Rational&, const Rational&);
   friend Rational operator/(const Rational&, const Rational&);
};


#endif // RATIONAL_H

// Rational.cpp
#include "Rational.h"

Rational::Rational(int numerator) : numer(numerator), denom(1)
{
}

Rational::Rational(int numerator, int denominator) : numer(numerator), denom(denominator)
{
}

Rational::Rational(const Rational& copy) : numer(copy.numer), denom(copy.denom)
{
}

Rational& Rational::operator=(const Rational& other)
{
    numer = other.numer;
    denom = other.denom;
}

Rational& Rational::operator=(int i)
{
    numer = i;
    denom = 1;
}

int nwd(int a, int b)
{
    if(a * b == 0)
        return 0;
    a = abs(a);
    b = abs(b);
    while(a != b)
    {
        if(a > b)
            a -= b;
        if(b > a)
            b -= a;
    }
    return a;
}

Rational Rational::operator++() const
{
    int a = numer + denom;
    Rational product(a, denom);
    return product;
}

Rational Rational::operator--() const
{
    int a = numer - denom;
    Rational product(a, denom);
    return product;
}

bool Rational::operator==(const Rational& other) const
{
    if(value() == other.value())
        return true;
    return false;
}

bool Rational::operator>=(const Rational& other) const
{
    if(value() >= other.value())
        return true;
    return false;
}

bool Rational::operator<=(const Rational& other) const
{
    if(value() <= other.value())
        return true;
    return false;
}

bool Rational::operator>(const Rational& other) const
{
    if(value() > other.value())
        return true;
    return false;
}

bool Rational::operator<(const Rational& other) const
{
    if(value() < other.value())
        return true;
    return false;
}

double Rational::value() const
{
    return 1.0 * numer / denom;
}

void Rational::initialize(int numerator, int denominator)
{
    numer = numerator;
    denom = denominator;
}

ostream& operator<<(std::ostream & str, const Rational & ob)
{
    if(ob.denom == 1)
    {
        str << ob.numer;
        return str;
    }
    if(ob.denom == -1)
    {
        str << "(-" << abs(ob.numer) << ")";
        return str;
    }
    if(ob.numer * ob.denom < 0)
        str << "(-" << abs(ob.numer) << "/" << abs(ob.denom) << ")";
    else
        str << abs(ob.numer) << "/" << abs(ob.denom);
    return str;
}

istream& operator>>(std::istream & str, Rational & ob)
{
    str >> ob.numer >> ob.denom;
    return str;
}

Rational operator+(const Rational& A, const Rational& B)
{
    int a = A.numer * B.denom + B.numer * A.denom;
    int b = A.denom * B.denom;
    int n = nwd(a,b);
    if(n == 0)
    {
        Rational product(0);
        return product;
    }
    a /= n;
    b /= n;
    Rational product(a,b);
    return product;
}

Rational operator-(const Rational& A, const Rational& B)
{
    int a = A.numer * B.denom - B.numer * A.denom;
    int b = A.denom * B.denom;
    int n = nwd(a,b);
    if(n == 0)
    {
        Rational product(0);
        return product;
    }
    a /= n;
    b /= n;
    Rational product(a,b);
    return product;
}

Rational operator*(const Rational& A, const Rational& B)
{
    int a = A.numer * B.numer;
    if(a == 0)
    {
        Rational product(0,1);
        return product;
    }
    int b = A.denom * B.denom;
    int n = nwd(a,b);
    a /= n;
    b /= n;
    Rational product(a,b);
    return product;
}

Rational operator/(const Rational& A, const Rational& B)
{
    int a = A.numer * B.denom;
    if(a == 0)
    {
        Rational product(0,1);
        return product;
    }
    int b = A.denom * B.numer;
    int n = nwd(a,b);
    a /= n;
    b /= n;
    Rational product(a,b);
    return product;
}