program smpl2
      implicit none         ! forces all variables to be declared
! a very simple program and here's a comment line
      real a,b,c,d,e
  20  format(3f8.4)
      open( unit=11, file='smpl2.in')  ! input file smpl2.in
      open( unit=12, file='smpl2.out') ! output file smpl2.out
      read(11,20) a,b,c
      write(12,20) a,b,c    ! write what you read
      close(11)             ! done with reading
! do some calculations
      d = a*b + c
      e = d*d
      write(12,*) 'some output',d,e
      close(12)
      stop
      end program smpl2