Odin lang

[SuperUserNameMan]

https://odin-lang.org/

fib.odin :

package main

import "core:fmt"

fib :: proc( n : u64 ) -> u64 {
	if n <= 1 {
		return n
	}

	return fib( n - 1 ) + fib( n - 2 )
}

main :: proc() {
	r := fib(47)

	fmt.println( r )
}

Compilation : ./odin build fib.odin -file -o:speed

Test : time ./fib

Result : 8.5 seconds

( For comparison : fib.c compiled using gcc -O3 is 5.3 seconds on my system )