1
CS 112 Introduction to
Programming
Lecture #34:
Data Structures:
Introduction and Linked Lists
http://flint.cs.yale.edu/cs112/
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Outline
qAdmin. and review
ØIntroduction to data structures
qLinked lists
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Data Structures: Motivation
rSome typical operations:
maccess the i-th element
minsert
•at the front
•at the back
•in the middle
mdelete
•the first element
•the last element
•the middle element
rQuestion: how many operations do we have to perform to
implement each of the above operations on an array?
data structures study how and what data are stored in a computer so that
operations can be implemented efficiently
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Outline
qAdmin. and review
rIntroduction to data structures
ØLinked lists
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Object References
rRecall that an object reference is a variable
that stores the address of an object
rA reference can also be called a pointer
student
John/
40725
Graphical representation:
class Student
{
private string name;
private int id;
…
}6
Recursive Data Structure: ListNode
object references can be used to create links between objects
class Student
{
private string name;
private int id;
public Student( string name, int id )
{
this.name = name; this.id = id;
}
public string ToString()
{
return String( “{0}/{1}”,
name, id )
}
}
class ListNode
{private object data;
// recursive data structure
private ListNode next;
public ListNode( object data)
{
this.data = data;
next = null;
}
public ListNode( object data,
ListNode next)
{
this.data = data;
this.next = next;
}
}
