IN FORTRAN

The greatest common divisor (GCD) of two integers a and b is the largest positive integer that divides both a and b. The Euclidean algorithm for finding GCD(a, b) is as follows: if b = 0, GCD(a, b) = a. Otherwise, let a = bq + r, where q is quotient and r is the remainder. Then GCD(a, b) = GCD(b, r). Write an external function subprogram to calculate the GCD of two integers. First, solve using a non-recursive algorithm and then by a recursive algorithm.

With

PROGRAM (name)

IMPLICIT NONE

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END PROGRAM (name)