demo_locate.f90 Source File

      program demo_locate
      use M_sort, only : sort_shell
      use M_list, only : locate
      implicit none
      character(len=:),allocatable  :: arr(:)
      integer                       :: i

      arr=[character(len=20) :: '', 'ZZZ', 'aaa', 'b', 'xxx' ]
      ! make sure sorted in descending order
      call sort_shell(arr,order='d')

      call update(arr,'b')
      call update(arr,'[')
      call update(arr,'c')
      call update(arr,'ZZ')
      call update(arr,'ZZZZ')
      call update(arr,'z')

      contains
      subroutine update(arr,string)
      character(len=:),allocatable :: arr(:)
      character(len=*)             :: string
      integer                      :: place, plus, ii, end
      ! find where string is or should be
      call locate(arr,string,place)
      write(*,*)'for "'//string//'" index is ',place, size(arr)
      ! if string was not found insert it
      if(place.lt.1)then
         plus=abs(place)
         ii=len(arr)
         end=size(arr)
         ! empty array
         if(end.eq.0)then
            arr=[character(len=ii) :: string ]
         ! put in front of array
         elseif(plus.eq.1)then
            arr=[character(len=ii) :: string, arr]
         ! put at end of array
         elseif(plus.eq.end)then
            arr=[character(len=ii) :: arr, string ]
         ! put in middle of array
         else
            arr=[character(len=ii) :: arr(:plus-1), string,arr(plus:) ]
         endif
         ! show array
         write(*,'("SIZE=",i0,1x,*(a,","))')end,(trim(arr(i)),i=1,end)
      endif
      end subroutine update
      end program demo_locate