1 files changed, 36 insertions, 0 deletions
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-09/src/main.rs b/src/doc/book/listings/ch04-understanding-ownership/listing-04-09/src/main.rs
new file mode 100644
index 000000000..5a6ceaa1e
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-09/src/main.rs
@@ -0,0 +1,36 @@
+// ANCHOR: here
+fn first_word(s: &str) -> &str {
+    // ANCHOR_END: here
+    let bytes = s.as_bytes();
+
+    for (i, &item) in bytes.iter().enumerate() {
+        if item == b' ' {
+            return &s[0..i];
+        }
+    }
+
+    &s[..]
+}
+
+// ANCHOR: usage
+fn main() {
+    let my_string = String::from("hello world");
+
+    // `first_word` works on slices of `String`s, whether partial or whole
+    let word = first_word(&my_string[0..6]);
+    let word = first_word(&my_string[..]);
+    // `first_word` also works on references to `String`s, which are equivalent
+    // to whole slices of `String`s
+    let word = first_word(&my_string);
+
+    let my_string_literal = "hello world";
+
+    // `first_word` works on slices of string literals, whether partial or whole
+    let word = first_word(&my_string_literal[0..6]);
+    let word = first_word(&my_string_literal[..]);
+
+    // Because string literals *are* string slices already,
+    // this works too, without the slice syntax!
+    let word = first_word(my_string_literal);
+}
+// ANCHOR_END: usage