anchor.diff:            write (*,8887)
             read *,stafile
             if (stafile.eq.'quit') stop
  +          if (stafile.eq.'help') call usage()
             goto 12
         else
              write(*,9999)
  
positive.code:           write (*,8888)
            read *,haffile
            if (haffile.eq.'quit') stop
            goto 13
        else
             write(*,9999)
  
negative.code:           write (*,8889)
            write (*,8886)
            read *,srcfile
            if (srcfile.eq.'quit') stop
            if (srcfile.eq.'help') call usage()
            goto 11
        else
             write(*,9999)
  