Greatest common divisor of four P57852

Write a function that computes the greatest common divisor of four natural numbers @a@, @b@, @c@ and @d@ using the fast version of the Euclidean algorithm.

Interface

int gcd4(int a, int b, int c, int d);

public static int gcd4(int a, int b, int c, int d);

gcd4(a, b, c, d)  # returns int

gcd4(a: int, b: int, c: int, d: int) -> int

Precondition

The four numbers are strictly greater than zero.

Observation

You only need to submit the required procedure; your main program will be ignored.

Hint

Using the function @gcd(a, b)@ of the exercise problem://problemsjutge.org:problems/p1/jpetit/mcd-iteratiu.pbm should be useful.