!************************************************************
!*   This small program finds coincidences of letters in    *
!*   two given words of up to 26 letters.                   *
!* -------------------------------------------------------- *
!* SAMPLE RUN:                                              *
!*                                                          *
!* Input first word : Bonjour                               *
!* Input second word: Monsieur                              *
!*                                                          *
!* The letter o is common to the two words.                 *
!* The letter n is common to the two words.                 *
!* The letter u is common to the two words.                 *
!* The letter r is common to the two words.                 *
!*                                                          *
!* -------------------------------------------------------- *
!* Reference: "Exercices en Turbo Pascal By Claude Delannoy *
!*             Eyrolles, 1997".                             *
!*                                                          *
!*                       F90 Release By J-P Moreau, Paris.  *
!*                              (www.jpmoreau.fr)           *
!************************************************************
Program Common_Letters

integer, parameter :: Lmax=26     !max. length of a word

character*Lmax mot1, &            !1st word
               mot2               !2nd word
logical  found                    !2 letters identical if TRUE
integer  i, j                     !loop counters
integer  l1,l2                    !length of mot1, mot2

! Read two words
  print *,' '
  write(*,10,advance='no'); read *, mot1
  write(*,20,advance='no'); read *, mot2
  print *,' '

  l1=Len_Trim(mot1)
  l2=Len_Trim(mot2)

! Compare the two words
  do i=1, l1
    found=.FALSE.
    j=1
    do while (found==.FALSE..and.j<=l2)
	  if (mot1(i:i)==mot2(j:j)) then
        print *, ' The letter ', mot1(i:i),' is common to the two words.'
        mot2(j:j)=' '     !to deactivate the found coincidence
        found=.TRUE.
      end if
      j=j+1
    end do
  end do
  print *,' '

10 format('  Input first word : ')
20 format('  Input second word: ')

End

! end of file comlet.f90