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C# Arrays stores a fixed-size sequential collection of elements of the same type. Instead of declaring individual variables, such as number0, number1, …, and number99, you declare one array variable such as numbers and use numbers[0], numbers[1], and …, numbers[99] to represent individual variables.

All arrays consist of contiguous memory locations. The lowest address corresponds to the first element and the highest address to the last element.

Declaring C# Arrays

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

datatype[] arrayName;

where,

For example,

double[] balance;

Initializing an Array

Declaring an array does not initialize the array in the memory. The 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

The index number, like −

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

The time of declaration, as shown −

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

Yo, u can also create and initialize an array, as shown −

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

You may also omit the size of the array, as shown −

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

Yo\u can copy an array variable into another target array variable. In such a case, both the target and source point to the same memory location −

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

When you create an array, the C# compiler implicitly initializes each array element to a default value depending on the array type. For example, 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];

The following example demonstrates the above-mentioned concepts 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]);
         }
         Console.ReadKey();
      }
   }
}

When the above code is compiled and executed, it produces the following result −

Element[0] = 100
Element[1] = 101
Element[2] = 102
Element[3] = 103
Element[4] = 104
Element[5] = 105
Element[6] = 106
Element[7] = 107
Element[8] = 108
Element[9] = 109

Using the foreach Loop

In the previous example, we used a for loop for accessing each array element. You can also use a for each statement to iterate through an array.

using System;

namespace ArrayApplication {
   class MyArray {
      static void Main(string[] args) {
         int []  n = new int[10]; /* n is an array of 10 integers */
         
         /* initialize elements of array n */
         for ( int i = 0; i < 10; i++ ) {
            n[i] = i + 100;
         }
         
         /* output each array element's value */
         foreach (int j in n ) {
            int i = j-100;
            Console.WriteLine("Element[{0}] = {1}", i, j);
         }
         Console.ReadKey();
      }
   }
}

When the above code is compiled and executed, it produces the following result −

Element[0] = 100
Element[1] = 101
Element[2] = 102
Element[3] = 103
Element[4] = 104
Element[5] = 105
Element[6] = 106
Element[7] = 107
Element[8] = 108
Element[9] = 109

C# Arrays

There are following few important concepts related to an array that should be clear to a C# programmer −

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