#include <iostream>
#include <vector>
#include <string>
using namespace std;
class Rational {
   private:
      int numerator;
      int denominator;
   public:
      Rational();
      explicit Rational(int);
      Rational(int, int);
      const Rational add(const Rational &) const;
      const Rational subtract(const Rational &) const;
      const Rational multiply(const Rational &) const;
      const Rational divide(const Rational &) const;
      void simplify();
      void display() const;
   private:
      int gcd(int, int) const;
};
Rational::Rational(){
    this->denominator = 1;
    this->numerator = 0;
}

Rational::Rational(int n, int d){
    this->numerator = n;
    this->denominator = d;
}

Rational::Rational(int n){
    this->numerator = n;
    this->denominator = 1;
}

const Rational Rational::add(const Rational &temp) const{
    Rational *r = new Rational();
    r->numerator = (this->numerator*temp.denominator + this->denominator*temp.numerator);
    r->denominator = (this->denominator * temp.denominator);
    return *r;
}

const Rational Rational::subtract(const Rational &temp) const {
    Rational *r = new Rational();
    r->numerator = (this->numerator*temp.denominator - this->denominator*temp.numerator);
    r->denominator = (this->denominator * temp.denominator);
    return *r;
}

const Rational Rational::multiply(const Rational &temp) const{
    Rational *r = new Rational();
    r->numerator = (this->numerator*temp.numerator);
    r->denominator = (this->denominator * temp.denominator);
    return *r;
}

const Rational Rational::divide(const Rational &temp) const {
    Rational *r = new Rational();
    r->numerator = (this->numerator*temp.denominator);
    r->denominator = (this->denominator * temp.numerator);
    return *r;
}
int Rational::gcd(int n, int d) const{
    int temp;
    while (d!= 0) {
        temp = n;
        n = d;
        d = temp % d;
    }
    return n;
}

void Rational::simplify(){
    this->numerator = this->numerator / gcd(numerator,denominator);
    this->denominator = this->denominator / gcd(numerator,denominator);
    return;
}

void Rational::display() const{
    cout << this->numerator <<" / "<< this->denominator;
}

Rational getRational();
void displayResult(const string &, const Rational &, const Rational&, const Rational&);

int main() {
   Rational A, B, result;
   int choice;

   cout << "Enter Rational A:" << endl;
   A = getRational();
   cout << endl;

   cout << "Enter Rational B:" << endl;
   B = getRational();
   cout << endl;

   cout << "Enter Operation (1 - 4):" << endl
      << "1 - Addition (A + B)" << endl
      << "2 - Subtraction (A - B)" << endl
      << "3 - Multiplication (A * B)" << endl
      << "4 - Division (A / B)" << endl
      << "5 - Simplify A" << endl;
   cin >> choice;
   cout << endl;

   if (choice == 1) {
      result = A.add(B);
      displayResult("+", A, B, result);
   } else if (choice == 2) {
      result = A.subtract(B);
      displayResult("-", A, B, result);
   } else if (choice == 3) {
      result = A.multiply(B);
      displayResult("*", A, B, result);
   } else if (choice == 4) {
      result = A.divide(B);
      displayResult("/", A, B, result);
   } else if (choice == 5) {
      A.simplify();
      A.display();
   } else {
      cout << "Unknown Operation";
   }
   cout << endl;

   return 0;
}

Rational getRational() {
   int choice;
   int numer, denom;

   cout << "Which Rational constructor? (Enter 1, 2, or 3)" << endl
      << "1 - 2 parameters (numerator & denominator)" << endl
      << "2 - 1 parameter (numerator)" << endl
      << "3 - 0 parameters (default)" << endl;
   cin >> choice;
   cout << endl;

   if (choice == 1) {
      cout << "numerator? ";
      cin >> numer;
      cout << endl;
      cout << "denominator? ";
      cin >> denom;
      cout << endl;
      return Rational(numer, denom);
   } else if (choice == 2) {
      cout << "numerator? ";
      cin >> numer;
      cout << endl;
      return Rational(numer);
   } else {
      return Rational();
   }
}

void displayResult(const string &op, const Rational &lhs, const Rational&rhs, const Rational &result) {
   cout << "(";
   lhs.display();
   cout << ") " << op << " (";
   rhs.display();
   cout << ") = (";
   result.display();
   cout << ")";
}