include c:\cxpl\codes;

func Fib(X);
int X;
        func ActualFib(N);
        int N;
        [if N<2 then return N
        else return ActualFib(N-1) + ActualFib(N-2);
        ]; \ActualFib;

[if X<0 then [Text(0, "Error "); return 0]
else return ActualFib(X);
]; \Fib;

[IntOut(0, Fib(8));  CrLf(0);
 IntOut(0, Fib(-2)); CrLf(0);
]