fn main() {

use std::collections::HashMap;
let text = "the quick brown fox jumps over the lazy dog the fox";
let mut counts: HashMap<&str, i32> = HashMap::new();
for word in text.split(' ') { *counts.entry(word).or_insert(0) += 1; }
println!("{} distinct words", counts.len());

assert_eq!(counts["the"],3); assert_eq!(counts["fox"],2);
}