# Arrays

of 21 introduction to arrays and its types

## Content

ARRAYS

WHY ARRAYS?

Why do we need arrays?

To handle similar types of data.

Imagine C programming without arrays.

Example, If the user want to store marks of 100
students, User may create 100 variables to store
data !!!

INTRODUCTION

An array is a sequence of data item of
homogeneous value(same type).
Stored at successive memory locations in
consecutive order.
Huge amount of data can be stored under
single variable name.
Searching of data item is faster.

ARRAY APPLICATIONS

Array Used for Maintaining multiple variable
names using single name
Array Can be Used for Sorting Elements
Array Can Perform Matrix Operations
Array Can be Used in CPU Scheduling
Array Can be Used in Recursive Function

Given a list of test scores, determine the maximum
and minimum scores.

ARRAY DECLARATION

Syntax:
Data type arrayName [ arraySize ];

Examples:
int

list;
char num;
float hat;

ARRAY INITIALIZATION
Example:

int num;

numreferences the first element in the array.

numreferences the last element in the array.

Arrays can be initialized at declaration time

int age={2,4,34,3,4};
int age[]={2,4,34,3,4}; - the compiler determines the
size of array by calculating the number of elements in
an array.

LENGTH OF ARRAYS

Once an array is created, its size is fixed. It
cannot be changed.

For Example,
int arr;

You can not insert any number to arr location because it
is not initialized.

ONE DIMENSIONAL ARRAY

ACCESSING ARRRAY ELEMENTS

Arrays can be accessed and treated like variables in
C.

scanf("%d",&age);

scanf("%d",&age[i]);

/* Statement to insert value in (i+1)th element of array age[].

printf("%d",age);

/* statement to insert value in the third element of array age[]. */

/* statement to print first element of an array. */

printf("%d",age[i]);

/* statement to print (i+1)th element of an array. */

SIMPLE PROGRAM
Program
#include <stdio.h>
void main()
{ int marks,i;
printf(“Input of Array

marks”);

for (i=0; i<5; i++)
scanf(“%d”, &marks[i]);
printf(“Output
of

Array marks”);

for (i=0; i<5; i++)
printf(“marks[%d]

%d ”, i, marks[i]);

=

Input of Array marks
(if you entered )
50
85
60
55
90
(you will get)
Output of Array marks
marks =50
marks = 85
marks = 60
marks = 55
marks = 90

TYPES OF ARRAYS

Single Dimensional Array
Two Dimensional Array
Multi Dimensional Array

TWO DIMENSIONAL ARRAY

What is a Two-dimensional array?

TWO DIMENSIONAL ARRAY
SYNTAX:
data-type name[row-size][column-size];
EXAMPLE:
int a;

INITIALIZATION

How to initialize a Two-Dimensional array?

Initialized directly in the declaration statement
 int b = {51, 52, 53, 54, 55, 56};
 b = 51 b = 52 b = 53
Use braces to separate rows in 2-D arrays.
 int c = {{1, 2, 3},
{4, 5, 6},
{7, 8, 9},
{10, 11, 12}};
 int c[ ] = {{1, 2, 3},
{4, 5, 6},
{7, 8, 9},
{10, 11, 12}};
Implicitly declares the number of rows to be 4.

INITIALIZATION

#include <stdio.h>

scanf("%f",&b[i][j]);

int main()

}

{

for(i=0;i<2;++i)

float a, b, c;

for(j=0;j<2;++j)

int i,j;

{

printf("Enter the elements of 1st matrix\n");
/* Reading two dimensional Array with the help of two for
loop. If there was an array of 'n' dimension, 'n' numbers of
loops are needed for inserting data to array.*/

/* Writing the elements of multidimensional array
using loop. */

c[i][j]=a[i][j]+b[i][j];
/* Sum of corresponding elements of two arrays. */ }

for(i=0;i<2;++i)

printf("\nSum Of Matrix:");

for(j=0;j<2;++j)

for(i=0;i<2;++i)

{

for(j=0;j<2;++j)

printf("Enter a%d%d: ",i+1,j+1);

{

scanf("%f",&a[i][j]);

printf("%.1f\t",c[i][j]);

}

if(j==1)

printf("Enter the elements of 2nd matrix\n");
for(i=0;i<2;++i)

printf("\n");

/* To display matrix sum in order. */

for(j=0;j<2;++j)

}

{

return 0;

printf("Enter b%d%d: ",i+1,j+1);

}

OUTPUT
Enter the elements of 1st matrix
Enter a11: 2;
Enter a12: 0.5;
Enter a21: -1.1;
Enter a22: 2;
Enter the elements of 2nd matrix
Enter b11: 0.2;
Enter b12: 0;
Enter b21: 0.23;
Enter b22: 23;
Sum Of Matrix: 2.2 0.5 -0.9 25.0

MULTI DIMENSIONAL ARRAY

MULTI DIMENSIONAL ARRAY
SYNTAX:
type array_name[d1][d2][d3][d4]………[dn];
EXAMPLE:
int table;

EXAMPLE
#include<stdio.h>
#include<conio.h>

{37, 38, 39}

void main()

},

{

};

int i, j, k;

clrscr();

int arr=

printf(":::3D Array Elements:::\n\n");

{

for(i=0;i<3;i++)

{
{11, 12, 13},
{14, 15, 16},
{17, 18, 19}
},
{
{21, 22, 23},
{24, 25, 26},

{
for(j=0;j<3;j++)
{
for(k=0;k<3;k++)
{
printf("%d\t",arr[i][j][k]);
}

{27, 28, 29}

printf("\n");

},

}

{

printf("\n");

{31, 32, 33},

}

{34, 35, 36},

getch();

}

THANK YOU

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