# Introduction to Arrays

### What is an array?

An Array is a collection of the elements of Similar Data-Type stored one after another in the memory.

### why do we use array ?


- We can overcome the disadvantage of using many variables since variables are used to store more than one element of the same datatype.

Types of arrays.
- 1D Array
- 2D Array
- 3D Array

Syntax to declare
```
Datatypes array_name[expression];
```

### Quick Note.
> ArraySize = No of elements * size of datatype

> Array indexing starts from 0


![A[3] (2).png](https://cdn.hashnode.com/res/hashnode/image/upload/v1626246523389/4uYM5mTp0.png)

### Different ways of array Initialization 


- 1. **Initializing all the memory location**

No of elements = Number of Elements
```
Int a[5] = { 10,20,30,40,50} 
```

- 2. **Partial Array Initialization** </br>
If the number of values initialized is less than the allocated memory then it is known as partial array initialization.

```
Int a[5] = { 10,20,30,40,70} 
```

- 3. **Initialization without size** 

The number of elements has not been specified to values specified.
```
int a [ ] = {10,20,30};
```
- 4.  **String Initialization **
Strings are defined as an array of characters with a null character in the end.

```
char str[50] = "GeeksforGeeks";

```

### Program to Read Array and print it.
```
#include<stdio.h>


int main()
{
int i,arr[10], range;

printf("Enter the number of elements in array:\n");
scanf("%d", &range);

printf("Enter the array elements:\n");
	for(i=0; i<range; i++)
	{
	scanf("%d", &arr[i]);
	}

printf("aray elements are as follows:");
	for(i=0; i<range; i++)
	{
	printf("%d ", arr[i]);
	}

}
```