How to declare a variable mid-routine in Fortran

Question

I would like to create an array with a dimension based on the number of elements meeting a certain condition in another array. This would require that I initialize an array

Answer 1

You can use allocatable arrays for this task:

subroutine example(some_array)

real             :: some_array(50)
real,allocatable :: new_array(:)
integer          :: i, element_count, status

element_count = 0
do i=lbound(some_array,1),ubound(some_array,1)
  if ( some_array(i) > 0 ) then
    element_count = element_count + 1
  endif
enddo

allocate( new_array(element_count), stat=status )
if ( status /= 0 ) stop 'cannot allocate memory'

! set values of new_array

end subroutine