This document discusses linear search. It contains the names of group members working on the topic. It then defines linear search as checking all elements of an array or structure sequentially until the desired result is found. It provides an example of searching for a phone number in a telephone directory. The document includes pseudocode and C++ code implementations of linear search. It discusses using linear search on a linked list. It covers the advantages of linear search running in constant time if the item is first in the list, and the disadvantages of search time increasing linearly with the number of elements.

1. Data Structure

2. Group Members
 MCS-13-08 Muhammed Talha
 MCS-13-03 Arslan Azam
 MCS-13-38 Aitazaz Ahsan
 MCS-13-39 Tayyaba Ghani
 MCS-13-22 Abida Bibi

3. Contents
Introduction to Search
What is Linear Search ?
Example of Linear Search ?
Pseudo code
C++ Code
linked list code of Linear Search
Worst Case
Best Case
Discussion

4. Muhammed Talha
Search
&
Linear Search

5. What is Search ?
 The definition of a search is the
process of looking for something or
someone
 Example : An example of a search is a
quest to find a missing person

6. Linear Search :
 Algorithm involves checking all the
elements of the array(or any other
structure) one by one and in sequence
until the desired result is found.

7. Linear Search Example
 If you are asked to find the name of the
person having phone number say “1234”
with the help of a telephone directory .
 Since telephone directory is sorted by
name not by numbers,we have to go
through each and every number of the
directory

8. Pseudocode
For all elements
Check if it is equal to element being
searched for.
If it is ,return its position.
else continue.

9. Arslan Azam
Linear Search Example by
C++ Program

10. C++ code
void iterSearch(const double data [ ],int n,double key)
//const for safety ,we want to keep array unchanged
{
for(int i=0;i<=n-1;i++)
//looping through all elements of the array
{
if(data[i]==key)
{
cout<<key<<" found at index "<<i<<" of the array"<<endl;
break;
//if element is found,come out of the loop
}
if(i==n-1)
//searched through the array,still not found
cout<<"n Element not found n";
}
}

11. Atizaz Ahsan
Linear Search Example by
using
Linked List

12. Linear Search using Linked List
 void List::find()
 {
 int n, count = 0;
 cout<<"Enter data to find in the list : ";
 cin>>n;
 Node *tmp = head;
 while ( tmp != NULL )
 {
 count = count + 1;
 if( n == tmp->Data())
 {
 cout<<"The data found on node number "<< count <<endl ;
 break;
 }
 tmp = tmp->Next();
 }

 }

13. Abida Bibi
Advantages
of
Linear Search

14. Advantages of Linear
search
 If the first number in the directory is the
number you were searching for ,then lucky
you!!.
 ●Since you have found it on the very first
page,now its not important for you that how
many pages are there in the directory.
 ●Whether if it is of 1000 pages or 2000
pages it will take u same time to find you
the number ,if it is at the very beginning .
 ●So it does not depends on no. on
elements in the directory.Hence constant
time .

15. Tayyaba Ghani
Disadvantages
of
Linear Search

16. Disadvantages of Linear search
 It may happen that the number you are searching for
is the last number of directory or if it is not in the
directory at all.
 In that case you have to search the whole directory.
 Now number of elements will matter to you.if there
are 500 pages ,you have to search 500;if it has 1000
you have to search 1000.
 Your search time is proportional to number of
elements in the directory.
No of elements No of comparisons to be done
15 15
600 600

17. Discussion
 1.Sorted array is not needed.
 2.Works fine for small number of
elements .Search time increases with
number of elements.
 3.Elements with higher probability of
being searched should be kept in the
beginning.

18. Question

19. Thank You 