[Rust] C-style struct demo.

// For abs function
use std::f64;

struct Point {
    x: f64,
    y: f64,
}

fn main() {
    let p = Point{ x: 3.0, y: 4.0 };

    assert!(f64::abs(p.x - 3.0) < 1e-10);
    assert!(f64::abs(p.y - 4.0) < 1e-10);
}