main.rs

use std::time::Instant;

#[derive(Debug)]
struct Entity {
    nid: u32,
    x: f64,
    y: f64,
    hp: u8,
    name: String
}

fn create_entity(nid: u32, x: f64, y: f64, name: String) -> Entity {
    Entity {
        nid,
        x,
        y,
        hp: 100,
        name
    }
}

fn main() {
    let mut entities: Vec<Entity> = Vec::new();
    for nid in 1..500000 {
        entities.push(create_entity(nid, 50.0, 50.0, String::from("entity") + &nid.to_string()));
    }

    let start = Instant::now();

    for entity in entities.iter_mut() {
        entity.x += 5.0;
        entity.y += 5.0;
    }
    println!("took {:?}", Instant::now() - start);
}