Fortran 95 source code to compute the G.C.D.

gcd.f95

!****************************************************
! 最大公約数計算
!
! date          name            version
! 2018.08.20    mk-mode.com     1.00 新規作成
!
! Copyright(C) 2018 mk-mode.com All Rights Reserved.
!****************************************************
!
program gcd_main
  implicit none

  write (*,*) gcd(144, 300)

  stop
contains
  ! 最大公約数計算
  !
  ! :param  integer a
  ! :param  integer b
  ! :return integer gcc
  integer function gcd(a, b)
    implicit none
    integer, intent(IN) :: a, b
    integer :: l, m, n

    m = a
    n = b

    do
      l = mod(m, n)
      if (l == 0) exit
      m = n
      n = l
    end do

    gcd = n

    return
  end function gcd
end program gcd_main