不会的就 match 一下

use std::io::{self,*};
//use std::str::FromStr;
fn main(){
    let stdin = io::stdin();
    for line in stdin.lock().lines() {
        let ll = line.unwrap();
        let mut v :Vec<char> = ll.chars().collect();
        for i in 0..v.len(){
            v[i] = match v[i] {
                'a'..='c' => '2',
                'd'..='f' => '3',
                'g'..='i' => '4',
                'j'..='l' => '5',
                'm'..='o' => '6',
                'p'..='s' => '7',
                't'..='v' => '8',
                'w'..='z' => '9',
                'A'..='Y' => {
                    let mut lowcase_plus_one = 'a'; 
                     for c in v[i].to_lowercase() {
                        lowcase_plus_one = (c as u8 + 1) as char;
                     }
                     lowcase_plus_one
                },
                'Z' => 'a',
                _ => v[i],
            };
        }
        println!("{}",v.iter().collect::<String>());
    }
}