DEFINE MAXSIZE="200"
BYTE ARRAY queue(MAXSIZE)
BYTE queueFront=[0],queueRear=[0]

BYTE FUNC IsEmpty()
  IF queueFront=queueRear THEN
    RETURN (1)
  FI
RETURN (0)

PROC Push(BYTE v)
  BYTE rear

  rear=queueRear+1
  IF rear=MAXSIZE THEN
    rear=0
  FI
  IF rear=queueFront THEN
    PrintE("Error: queue is full!")
    Break()
  FI
  queue(queueRear)=v
  queueRear=rear
RETURN

BYTE FUNC Pop()
  BYTE v

  IF IsEmpty() THEN
    PrintE("Error: queue is empty!")
    Break()
  FI
  v=queue(queueFront)
  queueFront==+1
  IF queueFront=MAXSIZE THEN
    queueFront=0
  FI
RETURN (v)

PROC TestIsEmpty()
  IF IsEmpty() THEN
    PrintE("Queue is empty")
  ELSE
    PrintE("Queue is not empty")
  FI
RETURN

PROC TestPush(BYTE v)
  PrintF("Push: %B%E",v)
  Push(v)
RETURN

PROC TestPop()
  BYTE v

  Print("Pop: ")
  v=Pop()
  PrintBE(v)
RETURN

PROC Main()
  TestIsEmpty()
  TestPush(10)
  TestIsEmpty()
  TestPush(31)
  TestPop()
  TestIsEmpty()
  TestPush(5)
  TestPop()
  TestPop()
  TestPop()
RETURN