my first rust code :)

lotterynumbers.rs

extern crate rand;
use rand::Rng;

fn main() {
    for i in 0..20 {
        println!("[{}.] {}", i + 1, output());
    }
}

fn get_lotterynumbers() -> Vec<i32> {
   let min = 1;
   let max = 49;
   let mut numbers = vec![];
   loop {
       let num = random_number(min, max);
       if numbers.contains(&num) {
          continue;
       } else {
            numbers.push(num);
       }
       if numbers.len() == 6 {
           break;
       }
   }
   numbers.sort();
   return numbers;
}

fn get_ticketnumbers() -> Vec<i32> {
   let min = 0;
   let max = 9;
   let mut numbers = vec![];
   loop {
       numbers.push(random_number(min, max));
       if numbers.len() == 7 {
           break;
       }
   }
   return numbers;
}

fn random_number(min: i32, max: i32) -> i32 {
   return rand::thread_rng().gen_range(min, max);
}

fn output() -> String {
    let lotterynumbers = get_lotterynumbers();
    let mut out_string = String::new();
    out_string.push_str("\n");
    out_string.push_str("lottery numbers: ");
    for i in lotterynumbers.iter() {
        out_string.push_str(&format!("| {} ", i));
    }

    let ticketnumbers = get_ticketnumbers();
    out_string.push_str(&format!("\nticketnumber:    ( "));
    for i in ticketnumbers.iter() {
        out_string.push_str(&format!("{} ", i));
    }
    out_string.push_str(")\n");
    return out_string;
}