! Elemental functions and subroutines are specified for scalar arguments
! but their beauty is that they can also be applied to arrays. However you 
! need to specify INTENT of the variables. Also dummy arguments and result 
! must not have the pointer attribute

program main
  implicit none
  real :: x(5),y(5)

  ! Uses the Fortran intrinsic 'sqrt'
  x=(/ 25.0, 16.0, 9.0, 4.0, 1.0 /)
  y=sqrt(x)
  print*, y

  ! Uses a user-defined subroutine 'my_sqrt_sub'
  y=0.0
  call my_sqrt_sub(x,y)
  print*, y

  ! Uses a user-defined function 'my_sqrt_func'
  y=0.0
  y=my_sqrt_func(x)
  print*, y

contains

  elemental subroutine my_sqrt_sub(a,b)
    implicit none
    real,intent(in) :: a
    real,intent(out) :: b
    b=(a)**(1.0/2.0)
  end subroutine my_sqrt_sub

  elemental function my_sqrt_func(a)
    implicit none
    real :: my_sqrt_func
    real, intent(in) :: a
    my_sqrt_func=(a)**(1.0/2.0)
  end function my_sqrt_func

end program main