Rust - counter

---

examples/files/counter/src/main.rs

use std::fs::File;
use std::io::Read;
use std::io::Write;

fn main() {
    let filename = "count.txt";
    let mut content = String::new();

    match File::open(filename) {
        Ok(mut file) => {
            file.read_to_string(&mut content).unwrap();
        }
        Err(_) => {
            content = String::from("0");
        }
    }
    let mut counter: i32 = content.trim().parse().expect("Wanted a number");
    counter += 1;
    println!("{}", counter);

    let mut file = File::create(filename).unwrap();
    writeln!(&mut file, "{}", counter).unwrap();
}