Cowgol

# Fibonacci calculator in Cowgol
include "cowgol.coh";

sub fibonacci(n: uint16): (result: uint16) is
    var a: uint16 := 0;
    var b: uint16 := 1;
    var i: uint16 := 0;
    var temp: uint16;

    if n == 0 then
        result := 0;
        return;
    end if;

    if n == 1 then
        result := 1;
        return;
    end if;

    while i < n - 1 loop
        temp := a + b;
        a := b;
        b := temp;
        i := i + 1;
    end loop;

    result := b;
end sub;

print("Fibonacci(10) = ");
print_i16(fibonacci(10));
print_newline();