iter on vec

src/main.rs

@@ -1,73 +1,9 @@
-struct Library {
-    books: Vec<Book>,
-}
-
-struct Book {
-    title: String,
-    year: u16,
-}
-
-impl Book {
-    fn new(title: &str, year: u16) -> Book {
-        Book {
-            title: String::from(title),
-            year,
-        }
-    }
-}
-
-impl std::fmt::Display for Book {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "{} ({})", self.title, self.year)
-    }
-}
-
-impl Library {
-    fn new() -> Library {
-        return Library { books: vec![] };
-    }
-
-    fn len(&self) -> usize {
-        return self.books.len();
-    }
-
-    fn is_empty(&self) -> bool {
-        return self.books.len() == 0;
-    }
-
-    fn add_book(&mut self, book: Book) {
-        self.books.push(book);
-    }
-
-    fn print_books(&self) {
-        if self.is_empty() {
-            println!("no books");
-            return;
-        }
-        for book in self.books.iter() {
-            println!("\"{}\" ({})", book.title, book.year);
-        }
-    }
-
-    fn oldest_book(&self) -> Option<&Book> {
-        self.books.iter().min_by(|x, y| x.year.cmp(&y.year))
-    }
-}
-
 fn main() {
-    let library: &mut Library = &mut Library::new();
+    let v: Vec<i8> = vec![10, 20, 30];
+    let mut iter = v.iter();
 
-    println!("our Library is empty: {}", library.is_empty());
+    println!("v[0]: {:?}", iter.next());
 
-    library.add_book(Book::new("Lord of the Rings", 1954));
-    library.add_book(Book::new("Alice's Adventures in Wonderland", 1865));
-
-    library.print_books();
-
-    match library.oldest_book() {
-        Some(book) => println!("My oldest book is {book}"),
-        None => println!("my library is empty!"),
-    }
-
-    println!("Our library has {} Books", library.len());
+    let v1: Option<&i8> = iter.next();
+    println!("v[1]: {v1:?}");
 }