random number generator
```rust extern crate randnumgen;
use randnumgen::{Rng, XorShift};
fn main() { let mut rng = XorShift::new(); let x: f32 = rng.next(); let y = rng.nextu32(); let z = rng.nextusize(); let w = rng.next_f64(); println!("{:?} {:?} {:?} {:?}", x, y, z, w); } ```