The Fibonacci calculator

The Fibonacci test was run with C, Perl, MatLab and on the TONS system. All programs implement a simple Fibonacci number calculator. The $n$'th Fibonacci number is defined as:

$$f(n) = \left\{ \begin{array}{r@{\quad:\quad}l} n & n \leq 2 \\ f(n-1) + f(n-2) & \mathrm{otherwise} \end{array}\right.$$