mod word_utils;
+use std::collections::HashMap;
+
use word_utils::{first_word, second_word};
-fn main() {
+fn test_strings() {
let s = String::from("Hello world");
println!("first word: '{}'", first_word(&s));
println!("second word: '{}'", second_word(&s).unwrap());
None => println!("match: second word of '{}' does not exist", s2),
}
}
+
+fn test_vectors() {
+ let v1 = vec![1, 2, 3];
+ println!("statically initialized vector: {:?}", v1);
+
+ let mut v2: Vec<String> = Vec::new();
+ v2.push("Hello".to_string());
+ v2.push(String::from("world"));
+ println!("dynamically built vector: {:?}", v2);
+ println!("first element: {}", v2[0]);
+ for el in &mut v2 {
+ *el += "xx";
+ }
+ for el in &v2 {
+ println!("{}", el);
+ }
+}
+
+fn test_hashmaps() {
+ let mut scores = HashMap::new();
+ scores.insert("john", 10);
+ scores.insert("mary", 20);
+
+ println!("scores: {:?}", scores);
+
+ // hash map with .collect()
+ let persons = vec![("homer", 42), ("marge", 30)];
+ let collect_scores: HashMap<_, _> = persons.into_iter().collect();
+ println!("collect_scores: {:?}", collect_scores);
+
+ for (p, s) in &collect_scores {
+ println!("person {}: score {}", p, s);
+ }
+
+ println!("john's score: {}", scores.get("john").unwrap());
+ println!("jake's score: {}", scores.get("jake").unwrap_or(&-1));
+
+ // double scores
+ for (_, v) in scores.iter_mut() {
+ *v *= 2;
+ }
+ println!("scores after doubling: {:?}", scores);
+
+ // double scores of immutable hashmap (rebuild it)
+ let collect_scores: HashMap<_, _> = collect_scores.iter()
+ .map(|(k, v)| (k, 2 * v))
+ .collect();
+ println!("collect_scores after rebuilding with doubling: {:?}", collect_scores);
+}
+
+fn main() {
+ test_strings();
+ test_vectors();
+ test_hashmaps();
+}