Arrays in C#

Declaring Arrays

To declare an array in C#, you can use the following syntax:

datatype[ ] arrayName;

where,

• datatype is used to specify the type of elements to be stored in the array.
• specifies the rank of the array. The rank specifies the size of the array.
• arrayName specifies the name of the array.

For example

double[ ] balance;

Initializing an Array

Declaring an array does not initialize the array in the memory. When the array variable is initialized, you can assign values to the array.

Array is a reference type, so you need to use the new keyword to create an instance of the array.

For example

double[ ] balance = new double[10];

Assigning Values to an Array

You can assign values to individual array elements, by using the index number, like:

double[ ] balance = new double[10];
balance[0] = 4500.0;

You can assign values to the array at the time of declaration, like:

double[ ] balance = { 2340.0, 4523.69, 3421.0};

You can also create and initialize an array, like:

int [ ] marks = new int[5] { 99, 98, 92, 97, 95};

In the preceding case, you may also omit the size of the array, like:

int [ ] marks = new int[ ] { 99, 98, 92, 97, 95};

You can also copy an array variable into another target array variable. In that case, both the target and source would point to the same memory location:

int [ ] marks = new int[ ] { 99, 98, 92, 97, 95};

int[ ] score = marks;

When you create an array, C# compiler implicitly initializes each array element to a default value depending on the array type. For example for an int array all elements would be initialized to 0.
Accessing Array Elements

An element is accessed by indexing the array name. This is done by placing the index of the element within square brackets after the name of the array. For example:

double salary = balance[9];

Following is an example which will use all the above mentioned three concepts viz. declaration, assignment and accessing arrays:

using System;

namespace ArrayApplication

{

class MyArray

{

static void Main(string[] args)

{

int[] n = new int[10]; /* n is an array of 10 integers */

int i, j;

/* initialize elements of array n */

for (i = 0; i < 10; i++)

{

n[i] = i + 100;

}

/* output each array element's value */

for (j = 0; j < 10; j++)

{

Console.WriteLine("Element[{0}] = {1}", j, n[j]);

}