An array is a sequential collection of variables of the same data type. In C#, an array can be single dimensional, multidimensional or jagged arrays. Each item of the can be accessed by its index number. By default, the index of the first element is 0.

Syntax and array decleration

An array can be declared by specifying its type name followed by square brackets ([]). 

datatype[] ArrayName;
  • datatype is the type of the elements of the array.
  • Size of the array can be specified in the [].
  • ArrayName is the name of the array.

Array initialization

int[] IntArray = new int[3] {10, 11};
char[] CharArray = new char[2] {'a', 'b'};

Assigning values

The value of any array element can be changed using its index.

char[] CharArray = new char[2] {'a', 'b'};
CharArray[1] = 'c';
//This will replace b with c

Accessing array elements

Array elements can be accessed using any of the below mentioned methods:

Using for loop:

using System;   //Adding namespaces
namespace LearnCSharp //Namespace of the class
{
class Program //The class
{
static void Main(string[] args) //Main method
{
//Declarig and Initializing array
int[] IntArray = new int[2] {10, 11};

//length of the array
int l = IntArray.Length;
for (int i = 0; i < IntArray.Length; i++ )
{
Console.WriteLine("Element at index {0}: {1}", i, IntArray[i]);
}
Console.ReadKey();
}
}
}

Output

Element at index 0: 10
Element at index 1: 11

Using foreach loop:

class Program   //The class
{
static void Main(string[] args) //Main method
{
//Declarig and Initializing array
char[] CharArray = new char[2] { 'a', 'b'};

foreach(char i in CharArray)
{
Console.WriteLine("Element : {0}", i);
}
Console.ReadKey();
}
}

Output

Element : a
Element : b

By specifying index:

static void Main(string[] args) //Main method
{
//Declarig and Initializing array
double[] DoubleArray = new double[2] { 3.14, 7.5};
Console.WriteLine("The element is: {0}", DoubleArray[1]);
Console.ReadKey();
}

Output – The element is: 7.5