Type tstack_node
	Field id% ; stack id; user defined
	Field value$ ; in this case a string
End Type


; push some values on different stacks
stack_push("0001",1)
stack_push("0002",1)
stack_push("a",2)
stack_push("b",2)
stack_push("anton",3)
stack_push("beton",3)
stack_push("0003",1)
stack_push("0004",1)

;pop and print values
Print(stack_pop(1))
Print(stack_pop(1))
Print(stack_pop(1))
Print(stack_pop(1))

Print(stack_pop(3))
Print(stack_pop(3))
Print(stack_pop(3))

Print(stack_pop(2))
Print(stack_pop(2))
Print(stack_pop(2))
Print(stack_pop(2))


WaitKey()


End


; ----------------------------------------------
; . functions


; ----------------------------------------------
; . stack_push()
Function stack_push(value$, stack_id%)
	sn.tstack_node = New tstack_node
	sn\id% = stack_id%
	sn\value$ = value$
End Function
; end of function stack_push()
; ----------------------------------------------


; ----------------------------------------------
; . stack_pop()
Function stack_pop$(stack_id%)
	sn.tstack_node = Last tstack_node
	
	While sn <> Null
		If sn\id% = stack_id% Then
			value$ = sn\value$
			Delete sn
			Return value$
		Else
			sn = Before sn
		End If
	Wend
End Function
; end of function stack_pop()
; ----------------------------------------------


; ----------------------------------------------
; . stack_empty()
Function stack_empty()
	For sn.tstack_node = Each tstack_node
		Delete sn
	Next
End Function
; end of function stack_empty()
; ----------------------------------------------


; end of functions
; ----------------------------------------------