Linked Lists

1
Linked Lists

• another data structure

2
Linked List

• another data structure for collections of objects
• used where an array could be used
• different strengths and weaknesses

3
Nodes

• a linked list is composed of objects called
  nodes
• nodes contain the data
• nodes link to eachother to make the lined list

4
Nodes example

• a linked list of integers is made of integer
  nodes
• each node contains one integer value
• each node is linked to another node

5
Nodes example java class

• public class IntNode
• private int data
• private IntNode link
• ...

247
data
data
link
link
6
Linked List of IntNodes

• each node contains an integer
• each node links to next node, except
• last node has null link

247
-59
119
8
data
data
data
data
link
link
link
link
7
Comparing array and linked list

• storing 4 integers in array

4
size
247
-59
119
8
?
?
?
?
vals
4
size
head
247
-59
119
8
data
data
data
data
link
link
link
link
8
Some lists

• empty list
• list with one item
• list with four items

0
size
head
1
66
size
data
head
link
4
size
247
-59
119
8
data
data
data
data
head
link
link
link
link
9
List from Nodes

• there is no linked list class
• lists exist as sets of nodes linked together
• in the collection object, the reference to the
  list is really a reference to the first node

10
IntNode class IntNode.java

• public class IntNode
• private int data
• private IntNode link
• constructors
• accessor methods for data, link
• modifier methods for data, link