! Example Fortran code

  program average

  ! Read in some numbers and take the average

  ! As written, if there are no data points, an average of zero is returned

  ! While this may not be desired behavior, it keeps this example simple

  implicit none

  real, dimension(:), allocatable :: points

  integer                         :: number_of_points

  real                            :: average_points=0., positive_average=0., negative_average=0.

  write (*,*) "Input number of points to average:"

  read  (*,*) number_of_points

  allocate (points(number_of_points))

  write (*,*) "Enter the points to average:"

  read  (*,*) points

  ! Take the average by summing points and dividing by number_of_points

  if (number_of_points > 0) average_points = sum(points) / number_of_points

  ! Now form average over positive and negative points only

  if (count(points > 0.) > 0) then

     positive_average = sum(points, points > 0.) / count(points > 0.)

  end if

  if (count(points < 0.) > 0) then

     negative_average = sum(points, points < 0.) / count(points < 0.)

  end if

  deallocate (points)

  ! Print result to terminal

  write (*,'(a,g12.4)') 'Average = ', average_points

  write (*,'(a,g12.4)') 'Average of positive points = ', positive_average

  write (*,'(a,g12.4)') 'Average of negative points = ', negative_average

  end program average