C# Arrays

In this chapter you will learn:

1. What is Array
2. How to create Array
3. Array for loop
4. Bounds Checking
5. Example to create an array and set value for each element
6. Create for loop to iterate C# array

Description

An array represents a fixed number of elements of a particular type.

All arrays inherit from the System.Array class, providing common services for all arrays.

Syntax

To declare a one-dimensional array, you will use this general form:

System.Array is a base class for all arrays in C#. Array elements can be of any type, including an array type.

An array is denoted with square brackets after the element type. For example:

Square brackets also index the array, accessing a particular element by position:

vowels [0] = 'a'; 
vowels [1] = 'e'; 
vowels [2] = 'i'; 
vowels [3] = 'o'; 
vowels [4] = 'u'; 
Console.WriteLine (vowels [1]);      // e 
/*  w ww  . ja v a2s  . c  om*/

This prints "e" because array indexes start at 0. We can use a for loop statement to iterate through each element in the array.

System.Array implements IEnumerable and IEnumerable<T>, you can use foreach iteration on all arrays in C#.

Arrays are zero indexed: an array with n elements is indexed from 0 to n-1.

using System;/*  www  . j a  v a2  s  . c  om*/

class MainClass
{
   static void Main()
   {
      int[] arr = new int[] { 15, 20, 5, 25, 10 };

      Console.WriteLine("GetType()    = {0}", arr.GetType());
   }
}

The code above generates the following result.

Array for loop

The for loop in this example cycles the integer i from 0 to 4:

for (int i = 0; i < vowels.Length; i++) {
       Console.Write (vowels [i]);            // aeiou 
}

Bounds Checking

All array indexing is bounds-checked by the runtime. If you use an invalid index, an IndexOutOfRangeException is thrown:

int[] arr = new int[3]; 
arr[3] = 1;// IndexOutOfRangeException thrown 

Example

The following code sets the elements in an array with index and then output them:

using System;//from  w w w. jav  a 2 s .co m

class Program
{
    static void Main(string[] args)
    {
        int[] intArray = new int[10];
        intArray[0] = 3;
        intArray[1] = 4;
        intArray[2] = 5;


        Console.WriteLine(intArray[0]);
        Console.WriteLine(intArray[1]);
        Console.WriteLine(intArray[2]);

    }
}

The output:

Example 2

We can use for loop the iterate each element in an array.

using System;/* ww w.j a  va  2s. c o m*/

class Program
{
    static void Main(string[] args)
    {
        int[] intArray = new int[10];

        for (int i = 0; i < intArray.Length; i++)
        {
            intArray[i] = i;
        }

        for (int i = 0; i < intArray.Length; i++)
        {
            Console.WriteLine(intArray[i]);
        }

    }
}

The output:

Next chapter...

What you will learn in the next chapter:

1. What is C# Array Length
2. How to access C# Array Length
3. How to use array length property
4. How to get array length with GetLength function
5. GetLength() and two dimension array

C# Arrays