PROGRAM CLASS_DEMO

CLASS QUEUE

   LOCAL SP
   LOCAL DIM STACK[100]

   FUNCTION ISEMPTY()
      ISEMPTY=(SP=0)
   END FUNCTION

   PROCEDURE INIT
      SP=0
   END PROCEDURE

   PROCEDURE POP(->XX)
      XX=STACK[SP]
      SP=SP-1
   END PROCEDURE

   PROCEDURE PUSH(XX)
      SP=SP+1
      STACK[SP]=XX
   END PROCEDURE

END CLASS

NEW PILA:QUEUE

BEGIN
    PILA_INIT  ! constructor
    FOR N=1 TO 4 DO  ! push 4 numbers
       PRINT("Push";N)
       PILA_PUSH(N)
    END FOR
    FOR I=1 TO 5 DO  ! pop 5 numbers
       IF NOT PILA_ISEMPTY() THEN
           PILA_POP(->N)
           PRINT("Pop";N)
         ELSE
           PRINT("Queue is empty!")
       END IF
    END FOR
    PRINT("* End *")
END PROGRAM