PHP convert decimal into fraction and back?

Question

I want the user to be able to type in a fraction like:

 1/2
 2 1/4
 3

And convert it into its corresponding decimal, to be saved in MySQL,

Answer 1

function dec2frac($f)
{
    $d = 1

    while (fmod($f, 1) != 0.0) {
        $f *= 2;
        $d *= 2;
    }

    $n = sprintf('%.0f', $f);
    $d = sprintf('%.0f', $d);

    return array($n, $d);
}

Then $f == $n / $d

For example:

print_r(dec2frac(3.1415926));

Outputs:

Array
(
    [0] => 3537118815677477  // $n
    [1] => 1125899906842624  // $d
)