Chapter 11

Data Structures

Understand Understand arraysarrays and their usefulness. and their usefulness.

Understand Understand recordsrecords and the difference between an array and and the difference between an array and a record.a record.

Understand the concept of a Understand the concept of a linked listlinked list and the difference and the differencebetween an array and a linked list.between an array and a linked list.

After reading this chapter, the reader should After reading this chapter, the reader should be able to:be able to:

OOBJECTIVESBJECTIVES

Understand Understand when to use an arraywhen to use an array and and when to use a linked-listwhen to use a linked-list..

Data Structures Data structure

uses a collection of related variables that can be accessed individually or as a whole.

Data structure a scheme for organizing related pieces of data. allowing different operations to be performed on the data.

The basic types of data structures include: files lists arrays records trees tables

ARRAYSARRAYSARRAYSARRAYS11.111.1

Array

Arraya fixed-size, sequenced collection of elements of the same data type.

The subscripts indicate the ordinal number of the element counting from the beginning of the array.

Figure 11-1Twenty individual variables

Figure 11-2 Processing individual variables

Figure 11-3 Arrays with subscripts and indexes

Figure 11-4 Processing an array

Figure 11-5 Frequency array Show the number of elements with the same

value found in a series of numbers.

Figure 11-6 Histogram

A pictorial representation of a frequency array.

Figure 11-7- Part I Two-dimensional array

Figure 11-8 Memory layout

Row-major storage

RECORDSRECORDSRECORDSRECORDS11.211.2

Record

Recorda collection of related elements, possibly of different types, having a single name.

Each element in a record is called a field.

Difference Array: all elements – same type Record: elements – same or different types.

Figure 11-9 Records

The elements in a The elements in a recordrecord can be can be of theof the

samesame or or differentdifferent types. types.

But all elementsBut all elementsin the record must be related.in the record must be related.

Note:Note:

LINKEDLINKEDLISTSLISTS

LINKEDLINKEDLISTSLISTS

11.311.3

Linked list

Linked listan ordered collection of data in which each element contains the location of the next element.

Each element contains two parts: data and link. The link contains a pointer (an address) that identifies the

next element in the list.

Singly linked list The link in the last element contains a null pointer,

indicating the end of the list.

Figure 11-10 Linked lists

Figure 11-11 Node

Nodes : the elements in a linked list.

The nodes in a linked list are called self-referential records. Each instance of the record contains a pointer to another

instance of the same structural type.

Figure 11-12 Inserting a node

Figure 11-13Deleting a node

Figure 11-14 Traversing a list