sort_int_array Subroutine

  subroutine sort_int_array(values)
    !! Sort an integer array in ascending order.
    implicit none

    ! Arguments
    integer, allocatable, intent(inout) :: values(:)
    !! Integer array sorted in ascending order in-place

    ! Local variables
    integer :: i, j, tmp
    !! Loop indices and swap temporary

    if(size(values) .le. 1) return

    do i = 1, size(values) - 1
       do j = i + 1, size(values)
          if(values(j) .lt. values(i))then
             tmp = values(i)
             values(i) = values(j)
             values(j) = tmp
          end if
       end do
    end do

  end subroutine sort_int_array