Rust perf test

perftest.rs

extern crate time;

use std::io;
use time::PreciseTime;

fn main() {
    let mut guess: String = String::new();
    io::stdin().read_line(&mut guess).expect("failed to read line");

    let n: i64 = guess.trim().parse().expect("Please type a number!");

    let start = PreciseTime::now();
    let sum = (1..n).fold(0, |sum, x| sum + x);
    let end = PreciseTime::now();

    println!("Time {}, Sum: {}", start.to(end), sum);

}