DEFINE MAXSIZE="200"
BYTE ARRAY stack(MAXSIZE)
BYTE stacksize=[0]

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

PROC Push(BYTE v)
  IF stacksize=maxsize THEN
    PrintE("Error: stack is full!")
    Break()
  FI
  stack(stacksize)=v
  stacksize==+1
RETURN

BYTE FUNC Pop()
  IF IsEmpty() THEN
    PrintE("Error: stack is empty!")
    Break()
  FI
  stacksize==-1
RETURN (stack(stacksize))

PROC TestIsEmpty()
  IF IsEmpty() THEN
    PrintE("Stack is empty")
  ELSE
    PrintE("Stack 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