• Source 
    1. fn remove_first(s: &str) -> Option<String> {
    2.     if s.len() == 0 {
    3.         return None;
    4.     }
    5.     let mut ret = String::new();
    6.     for (i, c) in s.chars().enumerate() {
    7.         if i > 0 {
    8.             ret.push(c);
    9.         }
    10.     }
    11.     Some(ret)
    12. }
    13.  
    14. fn main() {
    15.     let mut s = String::new();
    16.     std::io::stdin().read_line(&mut s).ok();
    17.  
    18.     println!("{:?}", remove_first(&s));
    19. }
    20.