RECURSIVE2

 !Program name: RECURSIVE2

program factorial

 

   integer :: n, f

   character (len=1) :: answer

   Print *, 'Input the value to be factorized: '

   Read *, n

 

   f = factorial(n)

   Print *, 'The value of factorial of', n, ' is: '

   Print *, f

10   Print *, 'Do you want to calculate another factorial (Y/N)?'

   Read *, answer

   If (answer == 'Y') then

        Print *, 'Input another value to be factorized: '

        Read *, n

        f = factorial(n)

        Print *, 'The value of the factorial of ', n, ' is: '

        Print *, f

        Go to 10

      else

      print *, 'Ok. Goodbye.'

   end if

 

end program factorial

 

! computes the factorial of n (n!)

recursive function factorial (n) result (f)

! function result

implicit none

 

   ! dummy arguments

   integer :: f

   integer, intent(in) :: n

 

   If (n == 0) then

      f = 1

      else

         f = n * factorial (n-1)  !the function is called recursively here

   end if

 

end function factorial