I have written a summation program that involves fractions and my limitations are to use the Rational.hpp file. I have written the code so that it gives the out put of the sum of 1/2 + 2/3 + 3/4 … 98/99 + 99/100, but the program returns a negative value. Is it possible that the variable gets overloaded and corrupted? if so, how would I work around the issue? Any help is greatly appreciated!

Edit: In response to the comments, I apologize if my question was phrased poorly and to clarify the only code I am responsible for writing is the Summation.cpp as the Rational.h is something provided by the education institution that I am currently trying to learn C++ from. Again I apologize for any misunderstanding I am a student doing my best to learn C++ and first time using stack overflow. Thank you patience.

    //Summation.cpp
    #include <iostream>
    #include "Rational.hpp"
    using namespace std;

    int main()
    {
      Rational sum(0, 1);
  
      for( int i = 1 ; i < 99; i++){
        cout << sum.doubleValue() << endl;
        Rational interval(i, i + 1);
        sum = sum.add(interval);
      }

      cout << "The sum of 1/2 through 99/100 is: " <<  sum.doubleValue() << endl;


      return 0;
    }

//Rational.hpp
#include <cstdlib> // For the abs function
#include <string>
using namespace std;

class Rational
{
public:
  Rational();
  Rational(int numerator, int denominator);
  int getNumerator() const;
  int getDenominator() const;
  Rational add(const Rational& secondRational) const;
  Rational subtract(const Rational& secondRational) const;
  Rational multiply(const Rational& secondRational) const;
  Rational divide(const Rational& secondRational) const;
  int compareTo(const Rational& secondRational) const;
  bool equals(const Rational& secondRational) const;
  int intValue() const;
  double doubleValue() const;
  string toString() const;

private:
  int numerator;
  int denominator;
  static int gcd(int n, int d);
};


Rational::Rational()
{
  numerator = 0;
  denominator = 1;
}

Rational::Rational(int numerator, int denominator)
{
  int factor = gcd(numerator, denominator);
  this->numerator = ((denominator > 0) ? 1 : -1) * numerator / factor;
  this->denominator = abs(denominator) / factor;
}

int Rational::getNumerator() const
{
  return numerator;
}

int Rational::getDenominator() const
{
  return denominator;
}

// Find GCD of two numbers 
int Rational::gcd(int n, int d) 
{
  int n1 = abs(n);
  int n2 = abs(d);
  int gcd = 1;

  for (int k = 1; k <= n1 && k <= n2; k++)
  {
    if (n1 % k == 0 && n2 % k == 0)
      gcd = k;
  }

  return gcd;
}

Rational Rational::add(const Rational& secondRational) const
{
  int n = numerator * secondRational.getDenominator() +
    denominator * secondRational.getNumerator();
  int d = denominator * secondRational.getDenominator();
  return Rational(n, d);
}

Rational Rational::subtract(const Rational& secondRational) const
{
  int n = numerator * secondRational.getDenominator()
    - denominator * secondRational.getNumerator();
  int d = denominator * secondRational.getDenominator();
  return Rational(n, d);
}

Rational Rational::multiply(const Rational& secondRational) const
{
  int n = numerator * secondRational.getNumerator();
  int d = denominator * secondRational.getDenominator();
  return Rational(n, d);
}

Rational Rational::divide(const Rational& secondRational) const
{
  int n = numerator * secondRational.getDenominator();
  int d = denominator * secondRational.numerator;
  return Rational(n, d);
}

int Rational::compareTo(const Rational& secondRational) const
{
  Rational temp = subtract(secondRational);
  if (temp.getNumerator() < 0)
    return -1;
  else if (temp.getNumerator() == 0)
    return 0;
  else
    return 1;
}

bool Rational::equals(const Rational& secondRational) const
{
  if (compareTo(secondRational) == 0)
    return true;
  else
    return false;
}

int Rational::intValue() const
{
  return getNumerator() / getDenominator();
}

double Rational::doubleValue() const
{
  return 1.0 * getNumerator() / getDenominator();
}

string Rational::toString() const
{
  if (denominator == 1)
    return to_string(numerator); // See Ch7 for to_string
  else
    return  to_string(numerator) + "/" + to_string(denominator);
}