Comparison between .len() and .chars().count()

main.rs

fn main() {

    let s1=String::from("ラウトは難しいです！");
    let len = calculate_length(&s1);
    let chars = calculate_characters(&s1);

    println!("The length of {:?} is {:?}.",s1,len);
    println!("The number of chars of {:?} is {:?}.",s1,chars);

}

fn calculate_length(s: &String)-> usize{
    s.len()
}

fn calculate_characters(s: &String)->usize{
    s.chars().count()
}