1. CS 280 Data Structures Professor John Peterson

2. Example 5 null 7 ab Link Data

3. Example 5 null 7 ab Link Data Link a = new Link () a.data = 5 Link b = new Link () b.data = 7 a.link = b

4. Example 5 null 7 ab Link Data Evaluate a.link a.data a.link.data b.link a.link.link b.data

5. Recursion Link is a recursive type – when you look inside you see another link It is natural to use recursion to program with linked lists Recursion = base case + recursive step

6. Example public static String print(List lst) { if (lst == null) return “{}”; return “{“ + print1(lst) + “}”; } public static String print1(List lst) if (lst.next == null) return l.data.toString(); return l.data.toString() + “, “ + print1(lst.next);

7. Iterative Version Public String print(List lst) { if (lst == null) return “{}”; String s = “”; while (lst.next != null) { s = s + lst.data.toString() + “, “; lst = lst.next; } return “{“ + s + lst.data.toString() + “}”; }