STACKSIZE = 1000

      FOR n = 3 TO 5
        PRINT "Push ";n : PROCpush(n)
      NEXT
      PRINT "Pop " ; FNpop
      PRINT "Push 6" : PROCpush(6)
      REPEAT
        PRINT "Pop " ; FNpop
      UNTIL FNisempty
      PRINT "Pop " ; FNpop
      END

      DEF PROCpush(n) : LOCAL f%
      DEF FNpop : LOCAL f% : f% = 1
      DEF FNisempty : LOCAL f% : f% = 2
      PRIVATE stack(), sptr%
      DIM stack(STACKSIZE-1)
      CASE f% OF
        WHEN 0:
          IF sptr% = DIM(stack(),1) ERROR 100, "Error: stack overflowed"
          stack(sptr%) = n
          sptr% += 1
        WHEN 1:
          IF sptr% = 0 ERROR 101, "Error: stack empty"
          sptr% -= 1
          = stack(sptr%)
        WHEN 2:
          = (sptr% = 0)
      ENDCASE
      ENDPROC