DS.ppt Datatastructures notes presentation

Definition
• Data structure is representation of the logical relationship existing
between individual elements of data.
• In other words, a data structure is a way of organizing all data items
that considers not only the elements stored but also their relationship to
each other.

Introduction
• Data structure affects the design of both structural & functional aspects
of a program.
Program=algorithm + Data Structure
• You know that a algorithm is a step by step procedure to solve a
particular function.

Introduction
• That means, algorithm is a set of instruction written to carry out
certain tasks & the data structure is the way of organizing the data
with their logical relationship retained.
• To develop a program of an algorithm, we should select an appropriate
data structure for that algorithm.
• Therefore algorithm and its associated data structures from a program.

Classification of Data Structure
• Data structure are normally divided into two broad categories:
•Primitive Data Structure
•Non-Primitive Data Structure

Data structure
Primitive DS Non-Primitive DS
Integer Float Character Pointer
Float
Integer Float

Non-Primitive DS
Linear List Non-Linear List
Array
Link List Stack
Queue Graph Trees

Primitive Data Structure
• There are basic structures and directly operated upon by the machine
instructions.
• In general, there are different representation on different computers.
• Integer, Floating-point number, Character constants, string constants,
pointers etc, fall in this category.

Non-Primitive Data Structure
• There are more sophisticated data structures.
• These are derived from the primitive data structures.
• The non-primitive data structures emphasize on structuring of a group
of homogeneous (same type) or heterogeneous (different type) data
items.

• Lists, Stack, Queue, Tree, Graph are example of non-primitive data
structures.
• The design of an efficient data structure must take operations to be
performed on the data structure.

• The most commonly used operation on data structure are broadly
categorized into following types:
• Create
• Selection
• Updating
• Searching
• Sorting
• Merging
• Destroy or Delete

Different between them
• A primitive data structure is generally a basic structure that is usually
built into the language, such as an integer, a float.
• A non-primitive data structure is built out of primitive data structures
linked together in meaningful ways, such as a or a linked-list, binary
search tree, AVL Tree, graph etc.

Description of various
Data Structures : Arrays
• An array is defined as a set of finite number of homogeneous
elements or same data items.
• It means an array can contain one type of data only, either all integer,
all float-point number or all character.

Arrays
• Simply, declaration of array is as follows:
int arr[10]
• Where int specifies the data type or type of elements arrays stores.
• “arr” is the name of array & the number specified inside the square
brackets is the number of elements an array can store, this is also
called sized or length of array.

Arrays
• Following are some of the concepts to be remembered about arrays:
•The individual element of an array can be
accessed by specifying name of the array,
following by index or subscript inside
square brackets.
•The first element of the array has index
zero[0]. It means the first element and last
element will be specified as:arr[0] & arr[9]
Respectively.

Arrays
•The elements of array will always be stored
in the consecutive (continues) memory
location.
•The number of elements that can be stored
in an array, that is the size of array or its
length is given by the following equation:
(Upperbound-lowerbound)+1

Arrays
•For the above array it would be
(9-0)+1=10,where 0 is the lower bound of
array and 9 is the upper bound of array.
•Array can always be read or written
through loop. If we read a one-dimensional
array it require one loop for reading and
other for writing the array.

Arrays
•For example: Reading an array
For(i=0;i<=9;i++)
scanf(“%d”,&arr[i]);
•For example: Writing an array
For(i=0;i<=9;i++)
printf(“%d”,arr[i]);

Arrays
•If we are reading or writing two-
dimensional array it would require two
loops. And similarly the array of a N
dimension would required N loops.
•Some common operation performed on
array are:
•Creation of an array
•Traversing an array

Arrays
•Insertion of new element
•Deletion of required element
•Modification of an element
•Merging of arrays

Lists
• A lists (Linear linked list) can be defined as a collection of variable
number of data items.
• Lists are the most commonly used non-primitive data structures.
• An element of list must contain at least two fields, one for storing data or
information and other for storing address of next element.
• As you know for storing address we have a special data structure of list
the address must be pointer type.

Lists
• Technically each such element is referred to as a node, therefore a list
can be defined as a collection of nodes as show bellow:
Head
AAA BBB CCC
Information field Pointer field
[Linear Liked List]

Lists
• Types of linked lists:
• Single linked list
• Doubly linked list
• Single circular linked list
• Doubly circular linked list

Stack
• A stack is also an ordered collection of elements like arrays, but it has
a special feature that deletion and insertion of elements can be done
only from one end called the top of the stack (TOP)
• Due to this property it is also called as last in first out type of data
structure (LIFO).

Stack
• It could be through of just like a stack of plates placed on table in a party, a
guest always takes off a fresh plate from the top and the new plates are
placed on to the stack at the top.
• It is a non-primitive data structure.
• When an element is inserted into a stack or removed from the stack, its base
remains fixed where the top of stack changes.

Stack
• Insertion of element into stack is called PUSH and deletion of
element from stack is called POP.
• The bellow show figure how the operations take place on a stack:
PUSH POP
[STACK]

Stack
• The stack can be implemented into two ways:
•Using arrays (Static implementation)
•Using pointer (Dynamic implementation)

Queue
• Queue are first in first out type of data structure (i.e. FIFO)
• In a queue new elements are added to the queue from one end called
REAR end and the element are always removed from other end called
the FRONT end.
• The people standing in a railway reservation row are an example of
queue.

Queue
• Each new person comes and stands at the end of the row and
person getting their reservation confirmed get out of the row from
the front end.
• The bellow show figure how the operations take place on a stack:
10 20 30 40 50
front rear

Queue
• The queue can be implemented into two ways:
•Using arrays (Static implementation)
•Using pointer (Dynamic implementation)

Trees
• A tree can be defined as finite set of data items (nodes).
• Tree is non-linear type of data structure in which data items are
arranged or stored in a sorted sequence.
• Tree represent the hierarchical relationship between various elements.

Trees
• In trees:
• There is a special data item at the top of hierarchy called the Root of
the tree.
• The remaining data items are partitioned into number of mutually
exclusive subset, each of which is itself, a tree which is called the sub
tree.
• The tree always grows in length towards bottom in data structures,
unlike natural trees which grows upwards.

Trees
• The tree structure organizes the data into branches, which related the
information.
A
B C
D E F G
root

Graph
• Graph is a mathematical non-linear data structure capable of
representing many kind of physical structures.
• It has found application in Geography, Chemistry and Engineering
sciences.
• Definition: A graph G(V,E) is a set of vertices V and a set of edges E.

Graph
• An edge connects a pair of vertices and many have weight such as
length, cost and another measuring instrument for according the
graph.
• Vertices on the graph are shown as point or circles and edges are
drawn as arcs or line segment.

Graph
• Example of graph:
v2
v1
v4
v5
v3
10
15
8
6
11
9
v4
v1
v2
v4
v3
[a] Directed &
Weighted Graph
[b] Undirected Graph

Graph
• Types of Graphs:
•Directed graph
•Undirected graph
•Simple graph
•Weighted graph
•Connected graph
•Non-connected graph

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