Language: C++

#[allow(unused_imports)]
use std::cmp::{max, min};
#[allow(unused_imports)]
use std::collections::{HashMap, HashSet};
#[allow(unused_imports)]
use std::io::*;
#[allow(unused_imports)]
use std::str::*;

#[allow(unused_macros)]
macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        let mut next = || { iter.next().unwrap() };
        input_inner!{next, $($r)*}
    };
    ($($r:tt)*) => {
        let stdin = std::io::stdin();
        let mut bytes = std::io::Read::bytes(std::io::BufReader::new(stdin.lock()));
        let mut next = move || -> String{
            bytes
                .by_ref()
                .map(|r|r.unwrap() as char)
                .skip_while(|c|c.is_whitespace())
                .take_while(|c|!c.is_whitespace())
                .collect()
        };
        input_inner!{next, $($r)*}
    };
}

#[allow(unused_macros)]
macro_rules! input_inner {
    ($next:expr) => {};
    ($next:expr, ) => {};

    ($next:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($next, $t);
        input_inner!{$next $($r)*}
    };
}

#[allow(unused_macros)]
macro_rules! read_value {
    ($next:expr, ( $($t:tt),* )) => {
        ( $(read_value!($next, $t)),* )
    };

    ($next:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($next, $t)).collect::<Vec<_>>()
    };

    ($next:expr, chars) => {
        read_value!($next, String).chars().collect::<Vec<char>>()
    };

    ($next:expr, usize1) => {
        read_value!($next, usize) - 1
    };

    ($next:expr, $t:ty) => {
        $next().parse::<$t>().expect("Parse error")
    };
}

#[allow(dead_code)]
fn read<T: FromStr>() -> T {
    let cin = stdin();
    let cin = cin.lock();
    let s: String = cin
        .bytes() // Bytes
        .map(|c| c.expect("failed reading char") as char)
        .skip_while(|c| c.is_whitespace()) // c が whitespace である限り skip
        .take_while(|c| !c.is_whitespace()) // c が whitespace でない限り要素を返す
        .collect();
    s.parse().ok().expect("failed parsing")
}

fn main() {
    let a: usize = read();
    let b: usize = read();
    let c: usize = read();
    println!("{}", max(max(a, b), c) - min(min(a, b), c));
}


Compiler output:
a.cc:1:2: error: invalid preprocessing directive #[
    1 | #[allow(unused_imports)]
      |  ^
a.cc:3:2: error: invalid preprocessing directive #[
    3 | #[allow(unused_imports)]
      |  ^
a.cc:5:2: error: invalid preprocessing directive #[
    5 | #[allow(unused_imports)]
      |  ^
a.cc:7:2: error: invalid preprocessing directive #[
    7 | #[allow(unused_imports)]
      |  ^
a.cc:10:2: error: invalid preprocessing directive #[
   10 | #[allow(unused_macros)]
      |  ^
a.cc:32:2: error: invalid preprocessing directive #[
   32 | #[allow(unused_macros)]
      |  ^
a.cc:43:2: error: invalid preprocessing directive #[
   43 | #[allow(unused_macros)]
      |  ^
a.cc:50:10: error: too many decimal points in number
   50 |         (0..$len).map(|_| read_value!($next, $t)).collect::<Vec<_>>()
      |          ^~~~~~~
a.cc:66:2: error: invalid preprocessing directive #[
   66 | #[allow(dead_code)]
      |  ^
a.cc:2:1: error: 'use' does not name a type
    2 | use std::cmp::{max, min};
      | ^~~
a.cc:4:1: error: 'use' does not name a type
    4 | use std::collections::{HashMap, HashSet};
      | ^~~
a.cc:6:1: error: 'use' does not name a type
    6 | use std::io::*;
      | ^~~
a.cc:8:1: error: 'use' does not name a type
    8 | use std::str::*;
      | ^~~
a.cc:11:1: error: 'macro_rules' does not name a type
   11 | macro_rules! input {
      | ^~~~~~~~~~~
a.cc:33:1: error: 'macro_rules' does not name a type
   33 | macro_rules! input_inner {
      | ^~~~~~~~~~~
a.cc:44:1: error: 'macro_rules' does not name a type
   44 | macro_rules! read_value {
      | ^~~~~~~~~~~
a.cc:67:1: error: 'fn' does not name a type
   67 | fn read<T: FromStr>() -> T {
      | ^~
a.cc:79:1: error: 'fn' does not name a type
   79 | fn main() {
      | ^~