Module_3_Arrays - Updated.pptx............

19/10/2024
Module 3
1
CSL 101-
Computer Programming
Computer Science and Engineering
Indian Institute of Information Technology,
Nagpur.
Varsha Kushwah

Arrays
• Array is a collection of similar data items or elements. Or we can say that array is a collection of homogeneous data
elements stored continuously under a single name. Array is defined as a set of homogeneous data items.
• Need for an array – When the number of variables of same type and nature are more then it is difficult to handle them.
So we need an array. Let us understand the use of array with an example:
#include <stdio.h>
int main() {
int i, a;
for(i=1;i<=5;i++)
{
printf(“nEnter the no.”);
scanf("%d", &a);
}
printf("Print the value of a %d", a);
return 0;
}

19/10/2024 3
• Declared using the following syntax
• type arrayname[size];
• Example:
int a[6];
• Here a is the name of the array.
• int is the data type of values which the array will store.
• 6 is the size of array and [] is called as subscript operator. The size of array must be a
constant.
• The most important thing is that all the values in the array should be of the same type.
Array Declaration

19/10/2024 4
• Initializing Arrays during Declaration
• Syntax: type arrayname[size] = {list of values};
• Example: int marks[5]={90, 82, 78, 95, 88};
Storing Values In Arrays:

19/10/2024 5
• Inputting Values from the Keyboard
int i, marks[5];
for(i=0; i<4; i++)
scanf("%d", &marks[i]);
• Assigning Values to Individual Elements
int marks[3];
marks[0] = 60;
marks[1] = 70;
marks[2] = 65;

19/10/2024 6

19/10/2024 7
• Address of data element A[k]
A[i] = BA + (i – lower_bound) * size
• BA is the base address of the array A,
• i is the index of the element of which we have to calculate the address,
• size is the size of one element in memory, i.e. size of int is 4
Address of Array Elements

19/10/2024 8
• Given an array
• int marks[8] = {99, 67, 78, 56, 88, 90, 34, 85}
• Calculate the address of marks[4] when the base address = 1000 when
integer size is 2 bytes.
Solution
marks[4] = 1000 + 2(4 – 0) = 1000 + 2(4) = 1008
Address of Array Elements

19/10/2024 9
• The length of an array is given by the number of elements stored in it
• General formula
• Length = upper_bound – lower_bound + 1
where
• upper_bound is the index of the last element
• lower_bound is the index of the first element
• Let Age[5] be an array of integers
Where Age[0] = 2, Age[1] = 5, Age[2] = 3, Age[3] = 1, Age[4] = 7.
Calculate the length of the array.
Calculating the Length of an Array

POINTS TO BE NOTED :
1) Array name should be unique
2) The elements in the array should be of same type
3) Subscript (array size) cannot be negative
4) Subscript must always be an integer

Types of Arrays
1) One Dimensional Array
2) Two Dimensional Array
3) Three Dimensional Array

• Arrays whose elements are specified by one subscript
are called One dimensional array or linear array.
• Syntax :
datatype arrayname[size];
• For Example :
• Note :
By default array index should starts with zero (0)
Single or One Dimensional
Arrays

PROGRAM-
Copy an array element to another array
#include <stdio.h>
int main()
{
int i, arr1[5] = {3, 4, 5, 1, 2};
int arr2[5];
for(i = 0; i < 5; i++)
{
arr2[i] = arr1[i];
printf("Elements in arr2: ");
for(i = 0; i < 5; i++)
{
printf("%d ", arr2[i]);
}
return 0;
}

PROGRAM-
Calculate the average
int i, sum = 0;
float average;
int marks[5] = {4,5,1,2,3};
for(i = 0; i < 5; i++)
sum += marks[i];
average = (float) sum/5;
Finding the largest element
int i, max;
int arr[10] = {4,5,6,1,2,3,7,8,9,10};
max = arr[0];
for (int i = ; i < 10; i++)
if (arr[i] > max)
max = arr[i];
printf("Largest element = %d", max);

Operations on Arrays
• Traversing an array
• Inserting an element in an array
• Searching an element in an array
• Deleting an element from an array
• Merging two arrays
• Sorting an array in ascending or descending order
• Traversing an Array
Accessing each and every element of the array
Traversing data elements of an array A can include
printing every element
counting the total number of elements
performing any process on these elements
Example
for (int i = 0; i < n; i++)
printf(“%dn”, arr[i]);

Search an element in an Array
arr[5] arr[6] arr[7] arr[8] arr[9]
120 124 128 132 136
10 20 30 40 50
100 104 108 112 116
flag = 0;
for(i = 0; i < n; i++)
if(arr[i] == val){
flag = 1;
break;
}
if(flag == 1)
printf("n Element is found at Position %d ", i+1);

Inserting an element in an Array
• Insertion at the End of an existing array
n = 5;
pos = 6;
val = 60;
arr[pos - 1] = val;
n++;
120 124 128 132 136
10 20 30 40 50
100 104 108 112 116

#include<stdio.h>
int main()
{
int arr[10],i,n;
printf("n Enter N Elements");
scanf("%d",&n);
if(n<=10 && n>=1 )
{
for(i=0;i<n;i++)
{
printf("enter arr[%d]=",i);
scanf("%d",&arr[i]);
}
for(i=0;i<n;i++)
{printf("%dn",arr[i]);}
}
else
{ printf("Envalid input");}
return 0;
}
Enter N Elements : 3
Enter arr[0] : 2
Enter arr[1] : 5
Enter arr[2] : 3
2
5
3
Write a program for entering data into an array &
Reading data from an array

Array Initialization
#include<stdio.h>
#include<conio.h>
void main()
{
int a[5]={10,20,30,40,50};
int i;
for(i=0;i<5;i++)
{
printf("%dn",a[i]);
}
}
10
20
30
40
50
PROGRAM-ARRAY INITIALIZATION

Output
#include <stdio.h>
int main() {
int arr[] = {1, 2, 2, 4, 2, 5, 5, 4, 7, 8, 8};
int n = sizeof(arr) / sizeof(arr[0]);
int visited[n];
for (int i = 0; i < n; i++)
{
visited[i] = 0;
}
for (int i = 0; i < n; i++)
{
if (visited[i] == 1)
{
continue;
}
int count = 1;
for (int j = i + 1; j < n; j++)
{
if (arr[i] == arr[j])
{
count++;
visited[j] = 1;
}
}
if (count > 1)
{
printf("Element %d is a duplicate and occurs %d times.n", arr[i], count);
}
}
return 0;
}
Element 2 is a duplicate and occurs 3 times.

19/10/2024 22
Program to print the largest and second
largest element of the array.

• A Arrays whose elements are specified by two subscript such
as row and column are called One dimensional array or
linear array.
• Row  means horizontally
• Column  means vertically
A two - dimensional array looks like a school time-table,
consisting of rows and columns.
A two – dimensional array is declared as –
– data_type array_name[row_size][column_size];
– Ex: int marks[2][3];
Two Dimensional Arrays

Two Dimensional Array Initialization
• Ex: Store the marks obtained by three students in five different subjects
int marks[3][5];
•Pictorial form of a two-dimensional array
The result of the above assignment will be as follows :

Storing a Two-Dimensional Array
• Row major order
– the elements of the array are stored row by row where n elements
of the first row will occupy the first n locations
•Column major order
– the elements of the array are stored column by column where m
elements of the first column will occupy the first m locations

Address of Array Element
• Formula to calculate the address of some element A[I][J]
When Array indices start with 1.
– Array elements are stored in row major order,
Address(A[I][J]) = BA + w{N(I – 1) + (J – 1)}
– Array elements are stored in column major order
Address(A[I][J]) = BA + w{M(J – 1) + (I – 1)}
where
w is the number of bytes required to store one element,
N is the number of columns,
M is the number of rows,
I and J are the subscripts of the array element.

Address of Array Element
• Consider a 20 x 5 two-dimensional array marks which has its
base address = 1000 and the size of an element = 2. Compute
the address of the element, marks[18][4] assuming that the
elements are stored in row major order, and array indices start
with 1.
•Solution
Address(A[I][J]) = BA + w{N(I – 1) + (J – 1)}
Address(marks[18][4]) = 1000 + 2 {5(18 – 1) + (4 – 1)}
= 1000 + 2 {5(17) + 3}
= 1000 + 2 (88)
= 1000 + 176 = 1176

19/10/2024 28
Write a “C” program to insert the elements matrices

Write a “C” program to perform the addition of two matrices
#include<stdio.h>
void main()
{
int a[3][3],b[3][3],c[3][3],i,j;
printf("Input A - Matrixn");
for(i=0;i<3;i++)
for(j=0;j<3;j++)
scanf("%d",&a[i][j]);
printf("Input B - Matrixn");
for(i=0;i<3;i++)
for(j=0;j<3;j++)
scanf("%d",&b[i][j]);
for(i=0;i<3;i++)
for(j=0;j<3;j++)
c[i][j]=a[i][j]+b[i][j];
printf("Sum of A and B Matrix=n");
for(i=0;i<3;++i)
{
for(j=0;j<3;++j)
printf("%d",c[i][j]);
printf("n");
}
}

Write a “C” program to perform the subtraction of two matrices
#include<stdio.h>
void main()
{
int a[3][3],b[3][3],c[3][3],i,j;
printf("Input A - Matrixn");
for(i=0;i<3;i++)
for(j=0;j<3;j++)
printf("Input B - Matrixn");
for(i=0;i<3;i++)
for(j=0;j<3;j++)
for(i=0;i<3;i++)
for(j=0;j<3;j++)
c[i][j]=a[i][j]-b[i][j];
printf("Sum of A and B Matrix=n");
for(i=0;i<3;++i)
{
for(j=0;j<3;++j)
printf("n");
}
}

Write a “C” program to perform matrix multiplication using two dimensional array
#include<stdio.h>
void main()
{
int a[10][10],b[10][10],c[10][10],i,j,m,n,p,q,k;
printf("Input row and column of A matrix n");
scanf("%d %d",&n,&m);
printf(" Input row and column of B matrix n");
scanf("%d %d",&p,&q);
if(m==p)
{
printf(" Matrices can be Multiplied: n");
printf(" Input A-matrix n");
for(i=0;i<n;++i)
for(j=0;j<m;++j)
printf(" Input B-matrix n");
for(i=0;i<p;++i)
for(j=0;j<q;++j)
printf("The resultant matrix ist:n");
for(i=0;i<n;++i)
{
for(j=0;j<m;++j)
{
c[i][j]=0;
for(k=0;k<p;++k)
c[i][j]=c[i][j] + a[i][k] * b[k][j];
}
printf("n
}
else
printf("Matrices cannot be multiplied n");
}

Session Summary
 Arrayname should be a unique and valid “C” Variable name
 The number of elements in a multi dimensional array is the product of its subscripts
 Arrays can be initialized to the same type in which they are declared
 The character array receives the terminating ‘0’ in the string constant
 The individual values in the array are called as elements
 It is not necessary to specify the length of an array, explicitly in case if initializers are
provided for the array during declaration itself

Module_3_Arrays - Updated.pptx............

More Related Content

Similar to Module_3_Arrays - Updated.pptx............ (20)

Recently uploaded (20)

Module_3_Arrays - Updated.pptx............

Editor's Notes