create a password with at least one uppercase letter in rust

main.rs
extern crate rand;

use rand::Rng;

fn main() {
    let mut rng = rand::thread_rng();

    // Generate a random password with 8 characters
    let password: String = rng.gen_ascii_chars().take(8).collect();

    // Convert the password to a vector of bytes
    let password_bytes = password.as_bytes();

    // Check if the password contains an uppercase letter
    let has_uppercase = password_bytes.iter().any(|b| b.is_ascii_uppercase());

    // If the password doesn't contain an uppercase letter, replace one of the lowercase letters with an uppercase letter
    if !has_uppercase {
        let mut new_password_bytes = password_bytes.to_owned();

        loop {
            // Choose a random index in the password string
            let i = rng.gen_range(0..8);

            // If the character at the index is a lowercase letter, replace it with an uppercase letter and break the loop
            if new_password_bytes[i].is_ascii_lowercase() {
                new_password_bytes[i] = new_password_bytes[i] - 32;
                break;
            }
        }

        // Convert the new password bytes to a string
        let new_password = String::from_utf8(new_password_bytes).unwrap();

        println!("Password: {}", new_password);
    } else {
        println!("Password: {}", password);
    }
}
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