C++ program with a self-designed class for rational numbers pairs not working as expected

Question

I have a problem with the code below. It is not performing any function now... neither add nor subtract nor divison nor multiplication.

Any help will be appreciated... I need explanation... so that I can understand it and get over with it :D

#include <iostream>
using namespace std;

// Class Definitions

class RationalNumber
{
public:
     RationalNumber(int, int, int, int);                    
     RationalNumber operator+(RationalNumber);
     RationalNumber operator-(RationalNumber);
     RationalNumber operator*(RationalNumber);
     RationalNumber operator/(RationalNumber);
     RationalNumber operator<(RationalNumber);
     RationalNumber operator>(RationalNumber);
     RationalNumber operator<=(RationalNumber);
     RationalNumber operator>=(RationalNumber);
     RationalNumber operator==(RationalNumber);
     RationalNumber operator!=(RationalNumber);
private:
     int numerator;
     int denominator;
     int numerator2;
     int denominator2;

};  // end RationalNumber class


// RationalNumber class member-function definitions
RationalNumber::RationalNumber(int num, int denom, int num2, int denom2)
{
     numerator = num;
     denominator = denom;
     numerator2 = num2;
     denominator2 = denom2;

//for first fraction
     if (denominator == 0 || denominator < 0)
          cout << "ERROR:Denominator can not be zero or less than zero." << "\n";

     else
          //Reduces the fraction to lowest terms.
     {
          int i = numerator > denominator ? numerator : denominator;

          while(i > 1)
          {
               if(numerator % i == 0 && denominator % i == 0)  
               {
               numerator /= i;
               denominator /= i;
               }
               --i;
          }

     }

     cout << "Simplified fraction one is: " << numerator << " / "
        << denominator << "\n";

//For second fraction
     if (denominator2 == 0 || denominator2 < 0)
          cout << "ERROR:Denominator can not be zero or less than zero" << "\n";
     else
          //Reduces the fraction to lowest terms.
     {
          int j = numerator2 > denominator2 ? numerator2 : denominator2;

          while(j > 1)
          {
               if(numerator2 % j == 0 && denominator2 % j == 0)  
               {
               numerator2 /= j;
               denominator2 /= j;
               }
               --j;
          }

     }
     cout << "Simplified fraction two is: " << numerator2 << " / "
        << denominator2 << "\n";

}

// addition operator
RationalNumber RationalNumber::operator+(RationalNumber a)
{
      RationalNumber temp=RationalNumber(1,2,3,4);
      temp.numerator = numerator + a.numerator;
      temp.denominator = denominator + a.denominator;
      temp.numerator2 = numerator2 + a.numerator2;
      temp.denominator2 = denominator2 + a.denominator2;
      return temp;
}

// subtraction operator
RationalNumber RationalNumber::operator-(RationalNumber a)
{
     RationalNumber temp=RationalNumber(1,2,3,4);
      temp.numerator = numerator - a.numerator;
      temp.denominator = denominator - a.denominator;
      temp.numerator2 = numerator2 - a.numerator2;
      temp.denominator2 = denominator2 - a.denominator2;
      return temp;
}

// multiplication operator
RationalNumber RationalNumber::operator*(RationalNumber a)
{
      RationalNumber temp=RationalNumber(1,2,3,4);
      temp.numerator = numerator * a.numerator;
      temp.denominator = denominator * a.denominator;
      temp.numerator2 = numerator2 * a.numerator2;
      temp.denominator2 = denominator2 * a.denominator2;
      return temp;
}

// division operator
RationalNumber RationalNumber::operator/(RationalNumber a)
{
      RationalNumber temp=RationalNumber(1,2,3,4);
      temp.numerator = numerator / a.numerator;
      temp.denominator = denominator / a.denominator;
      temp.numerator2 = numerator2 / a.numerator2;
      temp.denominator2 = denominator2 / a.denominator2;
      return temp;
}

int main()
{

     int top;
     int bot;
     int top2;
     int bot2;

     cout << "Please enter the Numerator for fraction one: \n";
     cin >> top;
     cout << "Please enter the Denominator for fraction one: \n";
     cin >> bot;
     cout << "Please enter the Numerator for fraction two: \n";
     cin >> top2;
     cout << "Please enter the Denominator for fraction two: \n";
     cin >> bot2;

     RationalNumber A(top, bot, top2, bot2);
     return 0;

}

Answer 1

By declaring RationalNumber(int, int, int, int), you automatically remove the default constructor, i.e. it is no longer possible to create an instance of your class by invoking a constructor without parameters.

In other words,

RationalNumber number;

is no longer possible. You'd need to say

RationalNumber number(1,2,3,4);.

If you want to be able to create an instance using a default constructor, then you need to define one in addition to the other constructor:

RationalNumber()
{
    // Initialization
}