Fib(n) {
nold1 := 1
nold2 := 0
If n < 0
{
MsgBox, Positive argument required!
Return
}
Else If n = 0
Return nold2
Else If n = 1
Return nold1
Fib_Label:
t := nold2+nold1
If n > 2
n--
nold2:=nold1
nold1:=t
GoSub Fib_Label
Return t