Why write fn main() -> io::Result{ in Rust like this?

Question

Rust

use std::io;
 
fn main()  -> io::Result<()>{
     
    let mut input = String::new();
    println!("Введите свое имя: ");
    io::stdin().read_line(&mut input)?;
    println!("Ваш имя: {}", input);
     
    Ok(())
}

Like what is this Result? It is not used anywhere in this code.

Answer 1

It is not used anywhere in this code.

Used.

use std::io;
 
fn main()  -> io::Result<()>{
     
    let mut input = String::new();
    println!("Введите свое имя: ");
    io::stdin().read_line(&mut input)?; // Тут
    println!("Ваш имя: {}", input);
     
    Ok(()) // И тут
}

Answer 2

https://qna.habr.com/q/1105214#answer_2097786