rust read int like characters

rust_int_char.rs

let a = "29";
    for c in a.chars() {
        println!("{}", c as u32 - 48);
    }

    let mut sum = 0;
    let x = 14183;
    let x = x.to_string();
    for y in x.chars() {
        // converting `y` to string and then to integer
       let z = (y.to_string()).parse::<i32>().unwrap();
        // incrementing `sum` by `z`
       sum += z;
    }
    println!("{}", sum);