fun with string slices

rustbook/ownership/src/main.rs

@@ -1,18 +1,26 @@
 fn main() {
-    let s = String::from("what the what");
+    let s = String::from("hello world");
-    let w = first_word(&s);
 
-    println!("w={}", w);
+    let word = first_word(&s[..]);
+    println!("word={}", word);
+
+    let l = "hello world";
+
+    let word = first_word(&l[..]);
+    println!("word={}", word);
+
+    let word = first_word(l);
+    println!("word={}", word);
 }
 
-fn first_word(s: &String) -> usize {
+fn first_word(s: &str) -> &str {
     let bytes = s.as_bytes();
 
     for (i, &item) in bytes.iter().enumerate() {
         if item == b' ' {
-            return i;
+            return &s[0..i];
         }
     }
 
-    s.len()
+    &s[..]
 }