program dice_gfortran
      implicit none
      integer i_answer, n
      real x

 100  write(*,*) 'Row a dice ? (1=Yes ; 0=No)'
      read(*,*) i_answer

      if ((i_answer.ne.0) .and. (i_answer.ne.1)) then
        write(*,*) '1 or 0 only, please.'
        goto 100 
      endif

      if (i_answer.eq.0) stop('Good luck!') ! g77 does not support this.
c     if (i_answer.eq.0) stop
     
      call random_number (x)
      n = int(6*x)+1
      write(*,*) 'call random_number(x) give you x=',x ,
     &'    Dice shows', n

      goto 100

      end