Challenge #236 [Easy] Random Bag System

main.rs

extern crate rand;

use rand::Rng;

struct Bag {
    contents: Vec<char>,
    rng: rand::ThreadRng,
}

impl Bag {
    fn new() -> Bag {
        Bag {
            contents: Vec::new(),
            rng: rand::thread_rng(),
        }
    }
}

impl Iterator for Bag {
    type Item = char;

    fn next(&mut self) -> Option<Self::Item> {
        if self.contents.is_empty() {
            // replenish the data
            
            // using extend like this will avoid allocating a whole new vector,
            // it'll just reuse the memory of the old one
            self.contents.extend(&['O', 'I', 'S', 'Z', 'L', 'J', 'T']);
            self.rng.shuffle(&mut self.contents);
        }
        self.contents.pop()
    }
}


fn main() {
    for c in Bag::new().take(50) {
        print!("{}", c);
    }
    print!("\n");
}