Conversions

[jynx678]

I have a fraction class, but I need to add functions that will convert a fraction to a float and vice versa. This is what I've been trying to work with. Thanks in advance

 Fraction Fraction (float rhs)
{
    Fraction temp;

    temp.WholeNumber = static_cast<int>(rhs);
    temp.Numerator = rhs  * 1000;
    temp.Denominator = 1000;
    ReduceFractions();

    return temp;
}
 operator float(const Fraction & rhs)
{
    Fraction lhs;
    float decimal;
    lhs.Numerator = (rhs.WholeNumber * rhs.Denominator) + rhs.Numerator;
    decimal = (float)rhs.Numerator / rhs.Denominator;
    return decimal;
}

[Duthomhas]

Unless explicitly required by the assignment to have a WholeNumber member, you should get rid of that.

class Fraction
{
  int Numerator;
  int Denominator;

  Fraction( int n, int d = 1 ): Numerator( n ), Denominator( d ) { }

  operator float ()  // remember, this is a conversion operator
  {                  // (converting from *this Fraction to a float)
    ...
  }

  Fraction( float f )  // and this is a constructor
  {                    // (converting from a float to *this Fraction)
    ...
  }
};

Anything you do to that (except set the denominator to zero) is a valid number.

All member functions should then work from that. To convert to a string, for example:

ostream& operator << ( ostream& outs, const Fraction& fraction )
{
  int whole     = fraction.Numerator / fraction.Denominator;
  int remainder = fraction.Numerator % fraction.Denominator;

  outs << whole << "+" << remainder << "/" << fraction.Denominator;

  return outs;
}

Now, to convert to a float, remember that a rational value is obtained from any fraction -- divide the numerator by the denominator using floating point division:

operator float ()
{
  return (float)fraction.Numerator / fraction.Denominator;
}

The code to convert from a float is a little more involved. Get ready by reading here first:
http://www.mathsisfun.com/converting-decimals-fractions.html

Fraction( float f )
{

If you want to make life easier, just pick some (large-ish) number to multiply by:

  Numerator   = f * 10000;  // (I would use a bigger number, personally)
  Denominator = 1 * 10000;

Now to simplify (or reduce) the fraction, just as in the example link above. To do it, you'll need the GCD (also called GCF).
http://stackoverflow.com/questions/10956543/gcd-function-in-c-sans-cmath-library

The GCD only works on unsigned values, so you'll have to make sure to have both Numerator and Denominator unsigned. Don't forget to remember the sign, though.

  int sign = 1;
  if ((Numerator * Denominator) < 0) sign = -1;
  Numerator   = abs( Numerator );
  Denominator = abs( Denominator );

Find the GCD of the numerator and denominator. Then divide both by it.

  int d = gcd( Numerator, Denominator );
  Numerator   /= d;
  Denominator /= d;

Don't forget the sign!

  Numerator *= sign;

Hope this helps.