Reducing fractions

Local $n = InputBox("Endless Love", "Enter the numerator of the fraction:")
Local $d = InputBox("Endless Love", "Enter the denominator of the fraction:")
If $d = 0 Then Exit MsgBox(0x10, "Error", "Denominator can't be zero!")

_ReduceFraction($n, $d)

MsgBox(0, "Endless Love", "Reduced fraction: " & ($n==0 ? $n : $n & "/" & $d))

; Reduce a fraction
Func _ReduceFraction(ByRef $iNumerator, ByRef $iDenominator)
    Local $iGCD = _GCD($iNumerator, $iDenominator)
    $iNumerator /= $iGCD
    $iDenominator /= $iGCD
    If $iDenominator < 0 Then
        $iNumerator = -$iNumerator
        $iDenominator = -$iDenominator
    EndIf
EndFunc


; Calculate the Greatest Common Divisor of $a and $b
Func _GCD($a, $b)
    $a = Abs($a)
    $b = Abs($b)

    If ($a = 0 Or $b = 0) Then Return $a + $b

    While ($a <> $b)
        If $a > $b Then
            $a -= $b
        Else
            $b -= $a
        EndIf
    WEnd
    Return $a
EndFunc