prime.ark

/**

Ark:
59.66
59.14
59.09
60.12
60.00
AVERAGE = 59.602

C:
58.63
58.57
59.01
50.53
59.81
AVERAGE = 57.31

Close! We had no optimization passes either!

**/

[c] func printf(fmt: ^u8, ...) -> int;
[c] func sqrt(x: f64) -> f64;

func is_prime(n: int) -> int {
    if n < 2 {
        return 0;
    } else if n == 2 {
        return 1;
    } else if n % 2 == 0 {
        return 0;
    }

    upper: int = int(C::sqrt(f64(n)));
    mut i: int = 3;

    for i <= upper {
        if n % i == 0 {
            return 0;
        }
        i = i + 2;
    }

    return i;
}

pub func main() -> int {
    mut no_primes: int = 0;
    limit: int = 67108864;
    mut n: int = 0;

    for n <= limit {
        if is_prime(n) >= 1 {
            no_primes = no_primes + 1;
        }
        n = n + 1;
    }

    C::printf(c"pi(%d) = %d\n", limit, no_primes);

    return 0;
}