# Array in Data Structure

An array is a collection of similar data items stored at contiguous memory locations.

For example,

## Example 01:

Array initialization:

``int a[6] = {2, 4, 6, 8, 10, 12};``

In above example,

• int is the type of the array
• ‘a’ is the name of the array
• a[6] shows number of elements in array
• Bracket {}, contains the array elements.
• Each element in array has its unique index number.

Index numbers of array elements in above example,

• 2 has index number 0
• 4 has index number 1
• 6 has index number 2
• 8 has index number 3
• 10 has index number 4
• 12 has index number 5

## Example 02:

``int a[ ] = {2, 4, 6, 8, 10, 12};``

This example is same as example 01 above. Only size of a[ ] is not defined.

## Multi-dimensional array:

### Three-dimensional array

Three-domensional array is like a cuboid.

## Syntax for arrays

```One-dimensional array
int arr[i];```
```Two-dimensional array
int arr[i][j];```
```Three-dimensional array
int arr[i][j][k];```

## Operations on array

1. Traversal : Visiting each element once.
2. Insertion : Process of inserting one or more elements in an array.
3. Deletion : Process of deleting one or more elements in an array.
4. Searching : Process of searching specific value in an array.
5. Sorting : Process of arranging elements in an array.

## How to access array elements ?

Here the array index number is used.

``````#include <stdio.h>
int main() {
int a[5] = {2,4,6,8,10};
printf("%d\n",a[0]); // Accessing using index number
printf("%d\n",a[1]);
printf("%d\n",a[2]);
printf("%d\n",a[3]);
printf("%d",a[4]);
return 0;
}``````