use std::env::args;
use std::mem::transmute;

fn main() {
    let x: f32 = args().skip(1).next().unwrap().parse().unwrap();
    let t = old_inv_sqrt(x);
    let h = inv_sqrt(x);
    let s = sqrt(x);

    println!("{}\n{}\n{}", t, h, s);
}

fn old_inv_sqrt(x: f32) -> f32 {
    let y: u32 = x.to_bits();
    let half: f32 = x * 0.5;

    let z: u64 = y as u64;
    let f: i64 = unsafe { transmute(z) };

    let r: i64 = 0x5f3759df - (f >> 1);
    let b: u64 = unsafe { transmute(r) };
    let b = b as u32;


    let a = f32::from_bits(b);

    a * (1.5 - (half * a * a))
}

fn inv_sqrt(x: f32) -> f32 {
    let i = x.to_bits();
    let s = 0x5f3759df - (i >> 1);
    let r = f32::from_bits(s);

    r * (1.5 - (x/2.0 * r * r))
}

fn sqrt(x: f32) -> f32 {
    let r = inv_sqrt(x);
    r * x
}