====== gcf ======
{{tag>math numerical_algorithms}}
''num gcf(num a, num b)''

[[:types|num - any numeric type (int or fixed)]]

===== Description =====
Returns the greatest common factor of two numbers.

The result will be negative if one or both arguments are negative.

===== Examples =====
<code>
gcf(18,   24) -> 6
gcf(-18,  24) -> -6
gcf(18,  -24) -> -6
gcf(-18, -24) -> -6

gcf(18.0,   24.0) -> 6.0
gcf(-18.0,  24.0) -> -6.0
gcf(18.0,  -24.0) -> -6.0
gcf(-18.0, -24.0) -> -6.0
</code>