Array in C Language

 INTRODUCTION

Arrays are used to store multiple values in a single variable, instead of declaring separate variables for each value.

There are 2 types of array : 1D array and 2D array.

1.1D Array :  

• It is a derived (we can create own data type) data type.
• All the elements in array are of same data type.(at a time we can use int/char/..cant use both at a time)
• No boundary.
• Elements store in a continuous memory allocation.

Syntax :

data_type array_name[size of array];

 

 eg.   int array[5]={1,2,3,4,5};

    - arrays index value starts with 0: array[0]=1,array[1]=2,array[2]=3,array[3]=4,array[4]=5

    - to change the element value ,refer index value. 

• we cant change the size of array after creation.

Example :

#include<stdio.h>

int main()

{

int array[10];

printf("enter 5 values of array :");

for(i=0; i=<4; i++)

{

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

}

for(i=0; i=<4; i++)

{

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

}

}

 

output :enter 5 values of array : 12345

1.2D Array : 

Two dimensional array can be defined as an array of array. It is also known as a matrix(a table of rows and columns).

Syntax :

data_type array_name[row][column] ;

eg.   int arr[4][4]={{2,1,2,2}, {1,8,1,0}, {3,5,9,1}, {5,4,6,8}};

  

$\left[\begin{array}{cccc}2& 1& 2& 2\\ 1& 8& 1& 0\\ 3& 5& 9& 1\\ 5& 4& 6& 8\end{array}\right]$

 - Rules to write 2D array :

1. int arr[2][3]; -----------valid
2. int arr[ ][3]; ------------valid
3. int arr[ ][ ]; --------------invalid
4. int arr[2][ ];-------------invalid
5. This 2D array program can be written in only nested loop.
   

 Example :

#include<stdio.h>

int arr[2][2];

int main()

{

int i,j;

for(i=0;  i<2;  i++)

{

for(j=0;  j<2;  j++)

{

print("enter value of array : \n");

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

}

}

for(i=0;  i<2;  i++)

{

for(j=0;  j<2;  j++)

{

printf("%d \t",arr[i][j]);

}

printf("\n");

}

}

output : 

enter value of array :

2

3

4

5

 

2 3

4 5