use std::env;
use thinset::{Pair, SparseMap};
fn main() {
let mut args = env::args();
args.next();
let s = args
.next()
.expect("Pass a string to count the number of characters of");
let mut map = SparseMap::new();
for ch in s.chars() {
map.update(ch as u8, |n| n + 1, 1);
}
println!("The following characters occur in the string '{}':", s);
for Pair { key, value } in map.iter() {
if *value == 1 {
println!(" '{}' once", *key as char);
} else {
println!(" '{}' {} times", *key as char, *value);
}
}
}