[Rust] C-style struct (mutable).

use std::f64;

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

fn main() {
    let mut p = Point{ x: 0.0, y: 0.0 };

    // Assign value to the field of struct Point
    p.x = 5.0;

    assert!(f64::abs(p.x - 5.0) < 1e-10);
}