! --- string having variable length ---
MODULE variable_string_data

  IMPLICIT NONE
  TYPE v_string
    CHARACTER(LEN=80) :: str
    INTEGER           :: ln
  END TYPE

CONTAINS

  FUNCTION fnc_length( s ) RESULT( length )

    IMPLICIT NONE
    CHARACTER(LEN=*), INTENT(IN) :: s   ! (1)
    INTEGER :: ls
    INTEGER :: length

    ls = LEN(s)                         ! (1)

    IF ( s(ls:ls) /= ' ' ) THEN
      length = ls
    ELSE IF ( s(ls-1:ls-1) /= ' ') THEN
      length = ls - 1
    ELSE
      length = INDEX(s,'  ') - 1        ! (2)
    END IF

  END FUNCTION

END MODULE
!
! main
!
PROGRAM main

  USE variable_string_data, ONLY : v_string, fnc_length
  IMPLICIT NONE
  TYPE(v_string) :: vst

  PRINT '(1X, A)', 'Input a sentence. : '
  READ '(A)', vst%str

  vst%ln = fnc_length( vst%str )
  PRINT '(1X, A, "(", I2, " )" )', vst%str(1:vst%ln), vst%ln

END PROGRAM main