#![allow(dead_code, deprecated, unused_variables, unused_mut)]
fn main() {
    let numbers = [1, 2, 3, 4, 5];
    let zero = "0".to_string();
    let result = numbers.iter().rfold(zero, |acc, &x| { format!("({x} + {acc})") });
    assert_eq!(result, "(1 + (2 + (3 + (4 + (5 + 0)))))");
}