C# Array

C# arrays is a collection of same datatype, which we can access using array index ( location of element inside array). Array elements are placed into contiguous memory locations.  So, array elements can be accessed by using array name and index number.

Index of array elements start from 0 and finish at n-1, where n = number of elements in the array. Consider a integer array sample as shown below, which shows array values and index number to access it's values

If name of an array is sample, then we can get second value(22) of array as sample[1], similarly, for third value (22), we can get it like sample[2]

Arrays can be 1-D array, 2-D arrays, 3-D arrays, Jagged arrays.

Declare array in C#

Here is the syntax to declare an array in C#

datatype arrayname[]; //we are declaring array here

Where,

datatype = can be of any datatype like int, string, char etc, which will be stored in an array

arrayname = name of the array

Example:

int[] arrInt;
string[] arrStr;

Define array in C#

Above, we have just declared the array, we haven't defined it, which we need to do, in order to use it.

Basically, while defining, we will be specifying the size of the array element.

Syntax

arrayname = new datatype[size];

arrayname = name of the array

new= keyword

datatype = type of data which will be stored in array

size = size of the array

Considering above example

arrInt= new int[5];

In the above sample, we are storing int array and array has can store upto 5 elements.

But, we can define and declare array in same one line as below

datatype[] arrayname = new datatype[size];

Example

int[] myArr = new int[5]; //int array with 5 elements size

Initialize array in C#

We have defined and decalred array until now, but haven't initialized it, we can initiliaze array by placing curly braces and placing values inside it, seperated by comma.

Example

int[] myArr= {10,5,6,7,8}; // int type arra initialized
string[] strArr= {"Mouse","Cat","Dog"}; //string array initialized

We can also declare and initialize array like this

int[ ] arr1 = new int[] { 1, 2, 3, 4, 5};
int[ ] arr2 = new int[5] { 1, 2, 3, 4, 5};

Example of C# Array

In this example, we will create a program to declare, initialize, and print an int array in C#

using System;
					
public class ArrayInCsharpProgram
{
	public static void Main()
	{
		int[] arrInt= new int[] {1,2,3,4,5};		
		int i;
        Console.WriteLine("Elements in the array are:");
        for ( i = 0; i < 5; i++ )
        {
           Console.WriteLine(arrInt[i]);
        }
		
	}
}

Output

Elements in the array are:
1
2
3
4
5

String array in C#

using System;
					
public class Program
{
	public static void Main()
	{
		    string[] names = {"John","Sam","Mick","jack"};
            Console.WriteLine("names[1] : "+names[1]);
            Console.WriteLine("names[3] : "+names[3]); 
       
	}
}

Output:

names[1] : Sam
names[3] : jack

In the above example, we are using string array to declare and initialize, then we are accessing array values using it's index location.

Looping array using ForEach loop in C#

using System;
					
public class ForEachCsharpProgram
{
	public static void Main()
	{
		    string[] names = {"John","Sam","Mick","jack"};
            Console.WriteLine("Elements in the array are:");
			foreach (string str in names)
			{
			   Console.WriteLine(str);
			}
       
	}
}

Output:

Elements in the array are:
John
Sam
Mick
jack

Foreach loop is an easy way to loop array or collections in C#. Foreach loop syntax

foreach (datatype element in iterable-item-like-array)
{
    // body of foreach loop
}

Where datatype, can be any datatype like int, char, string.

We are using in keyword within foreach loop to iterate over the iterable-item-like-array. The in keyword selects an item from the iterable-item-likearray on each iteration and store it in the variable element, which we can use inside foreach loop body.