Example of a solution to the telegram problem using channels in Rust

telegram.rs

use std::sync::mpsc::channel;
use std::thread;

fn main() {

    let line_length = 40;
    let input = vec!("The task is",
                     "to write a program which",
                     "accepts",
                     "lines of text and generates output",
                     "lines of",
                     "a different length, without splitting any of the",
                     "words in the text. We assume no word is longer than the size of",
                     "the output lines.");


    let (tx, rx) = channel();
    for i in input {
        let words = i.split(' ');


        for word in words {
            let tx = tx.clone();
            thread::spawn(move || {
                tx.send(word).unwrap();
            });
        }
    }
    drop(tx);

    let mut lines: Vec<String> = Vec::new();
    let mut buf = String::new();
    for word in rx.iter() {
        if buf.len() + word.len() > line_length {
            buf.pop(); // remove space char at end of line
            lines.push(buf.clone());
            buf.clear();
        }

        buf.push_str(word);
        buf.push(' ');
    }
    lines.push(buf);

    for line in lines {
        println!("{}", line);
    }
}