Update Fortran

1 files changed, 52 insertions, 0 deletions

diff --git a/gcd.f90 b/gcd.f90
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+! SYNOPSIS:
+!
+! # gfortran -o gcd-f gcd.f90
+! # ./gcd-f 11 22 33 121
+!
+
+program GCD
+  implicit none
+
+  integer, allocatable :: ns(:)
+  integer :: i, n
+  character(len=20) :: tmpstr
+
+  n = command_argument_count()
+
+  allocate (ns(n))
+
+  do i = 1, n
+    call get_command_argument(i, tmpstr)
+    ns(i) = str2int(tmpstr)
+  end do
+
+  print '(I0)', gcdn(ns)
+
+  deallocate (ns)
+
+contains
+
+  pure integer function str2int(s)
+    character*(*), intent(in) :: s
+    read (s, *) str2int
+  end function
+
+  pure recursive integer function gcd2(a, b) result(GCD)
+    integer, intent(in) :: a, b
+    if (b == 0) then
+      GCD = a
+    else
+      GCD = gcd2(b, mod(a, b))
+    end if
+  end function gcd2
+
+  pure integer function gcdn(n)
+    integer, intent(in) :: n(:)
+    integer :: i
+    gcdn = n(1)
+    do i = 2, size(n)
+      gcdn = gcd2(gcdn, n(i))
+    end do
+  end function
+
+end program