Data structure of using c

Module-1
Lecture-01
Introduction to Data structures
In computer terms, a data structure is a Specific way to store and organize data in a
computer's memory so that these data can be used efficiently later. Data may be
arranged in many different ways such as the logical or mathematical model for a
particular organization of data is termed as a data structure. The variety of a particular
data model depends on the two factors -
 Firstly, it must be loaded enough in structure to reflect the actual relationships of
the data with the real world object.
 Secondly, the formation should be simple enough so that anyone can efficiently
process the data each time it is necessary.
Categories of Data Structure:
The data structure can be sub divided into major types:
 Linear Data Structure
 Non-linear Data Structure
Linear Data Structure:
A data structure is said to be linear if its elements combine to form any specific order.
There are basically two techniques of representing such linear structure within memory.
 First way is to provide the linear relationships among all the elements
represented by means of linear memory location. These linear structures are termed as
arrays.
 The second technique is to provide the linear relationship among all the elements
represented by using the concept of pointers or links. These linear structures are
termed as linked lists.
The common examples of linear data structure are:
 Arrays
 Queues
 Stacks
 Linked lists
Non linear Data Structure:
This structure is mostly used for representing data that contains a hierarchical
relationship among various elements.
Examples of Non Linear Data Structures are listed below:
 Graphs
 family of trees and
 table of contents
Tree: In this case, data often contain a hierarchical relationship among various
elements. The data structure that reflects this relationship is termed as rooted tree
graph or a tree.

,Graph: In this case, data sometimes hold a relationship between the pairs of elements
which is not necessarily following the hierarchical structure. Such data structure is
termed as a Graph.
Array is a container which can hold a fix number of items and these items should be of
the same type. Most of the data structures make use of arrays to implement their
algorithms. Following are the important terms to understand the concept of Array.
 Element − Each item stored in an array is called an element.
 Index − Each location of an element in an array has a numerical index, which is
used to identify the element.
Array Representation:(Storage structure)
Arrays can be declared in various ways in different languages. For illustration, let's take
C array declaration.




Arrays can be declared in various ways in different languages. For illustration, let's take
C array declaration.




As per the above illustration, following are the important points to be considered.
 Index starts with 0.
 Array length is 10 which means it can store 10 elements.
 Each element can be accessed via its index. For example, we can fetch an
element at index 6 as 9.
Basic Operations
Following are the basic operations supported by an array.
 Traverse − print all the array elements one by one.
 Insertion − Adds an element at the given index.
 Deletion − Deletes an element at the given index.
 Search − Searches an element using the given index or by the value.
 Update − Updates an element at the given index.
In C, when an array is initialized with size, then it assigns defaults values to its
elements in following order.
Data Type Default Value

bool false

, char 0

int 0

float 0.0

double 0.0f

void

wchar_t 0
Insertion Operation
Insert operation is to insert one or more data elements into an array. Based on the
requirement, a new element can be added at the beginning, end, or any given index of
array.
Here, we see a practical implementation of insertion operation, where we add data at
the end of the array −
Algorithm
Let LA be a Linear Array (unordered) with N elements and K is a positive integer such
that K<=N. Following is the algorithm where ITEM is inserted into the K th position of LA
−
1. Start
2. Set J = N
3. Set N = N+1
4. Repeat steps 5 and 6 while J >= K
5. Set LA[J+1] = LA[J]
6. Set J = J-1
7. Set LA[K] = ITEM
8. Stop
Example
Following is the implementation of the above algorithm −
Live Demo
#include <stdio.h>

main() {
int LA[] = {1,3,5,7,8};
int item = 10, k = 3, n = 5;
int i = 0, j = n;
printf("The original array elements are :\n");
for(i = 0; i<n; i++) {
printf("LA[%d] = %d \n", i, LA[i]);
}

, n = n + 1;
while( j >= k) {
LA[j+1] = LA[j];
j = j - 1;
}
LA[k] = item;
printf("The array elements after insertion :\n");
for(i = 0; i<n; i++) {
printf("LA[%d] = %d \n", i, LA[i]);
}
}
When we compile and execute the above program, it produces the following result −
Output
The original array elements are :
LA[0] = 1
LA[1] = 3
LA[2] = 5
LA[3] = 7
LA[4] = 8
The array elements after insertion :
LA[0] = 1
LA[1] = 3
LA[2] = 5
LA[3] = 10
LA[4] = 7
LA[5] = 8
Deletion Operation
Deletion refers to removing an existing element from the array and re-organizing all
elements of an array.
Algorithm
Consider LA is a linear array with N elements and K is a positive integer such
that K<=N. Following is the algorithm to delete an element available at the Kth position
of LA.
1. Start
2. Set J = K
3. Repeat steps 4 and 5 while J < N
4. Set LA[J] = LA[J + 1]
5. Set J = J+1
6. Set N = N-1
7. Stop
Example