length := fn(ptr: ^u8): int {
	len := 0
	loop if *(ptr + len) == 0 break else len += 1
	return len
}

// WTFFF is wrong with display_int
display_int := fn(num: int, p: ^u8): ^u8 {
	ptr := p
	negative := num < 0
	if negative {
		num = -num
	}
	if num == 0 {
		*ptr = 48
		ptr += 1
	} else {
		loop if num == 0 break else {
			*ptr = num % 10 + 48
			ptr += 1
			num /= 10
		}
	}
	if negative {
		*ptr = 45
		ptr += 1
	};
	*ptr = 0
	@inline(reverse, p)
	return p
}

reverse := fn(s: ^u8): void {
	//reverse a string, don't remove digits
	len := 0
	loop if *(s + len) == 0 break else len += 1
	i := 0
	j := len - 1
	temp := 0
	loop if i >= j break else {
		temp = *(s + i);
		*(s + i) = *(s + j);
		*(s + j) = temp
		i += 1
		j -= 1
	}
	return
}