C# Arrays

Arrays are used to store multiple values in a single variable, instead of declaring separate variables for each value.

To declare an array, define the variable type with square brackets:

string[] cars;

We have now declared a variable that holds an array of strings. To insert values to it, use an array literal - place the values in a comma-separated list, inside curly braces:

string[] cars = {"Volvo", "BMW", "Ford", "Mazda"};

Access the Elements of an Array

You access an array element by referring to the index number.

This statement accesses the value of the first element in cars:

string[] cars = {"Volvo", "BMW", "Ford", "Mazda"};
Console.WriteLine(cars[0]); // Outputs Volvo

Note: Array indexes start with 0: [0] is the first element. [1] is the second element, etc.

Array Length

To find out how many elements an array has, use the Length property:

Console.WriteLine(cars.Length);

Examples

Create and Access Array

Outputs the first element.

using System;

class Program
{
  static void Main(string[] args)
  {
    string[] cars = {"Volvo", "BMW", "Ford", "Mazda"};
    Console.WriteLine(cars[0]);
  }
}

Change Array Element

Changing the first element.

using System;

class Program
{
  static void Main(string[] args)
  {
    string[] cars = {"Volvo", "BMW", "Ford", "Mazda"};
    cars[0] = "Opel";
    Console.WriteLine(cars[0]);
  }
}

Array Length

Getting the number of elements.

using System;

class Program
{
  static void Main(string[] args)
  {
    string[] cars = {"Volvo", "BMW", "Ford", "Mazda"};
    Console.WriteLine(cars.Length);
  }
}

Loop Through an Array

Using a for loop.

using System;

class Program
{
  static void Main(string[] args)
  {
    string[] cars = {"Volvo", "BMW", "Ford", "Mazda"};
    for (int i = 0; i < cars.Length; i++) 
    {
      Console.WriteLine(cars[i]);
    }
  }
}

Foreach Loop Array

Cleaner syntax for looping.

using System;

class Program
{
    static void Main()
    {
        int[] numbers = {1, 2, 3, 4, 5};
        foreach (int i in numbers)
        {
            Console.WriteLine(i);
        }
    }
}

Sort an Array

Alphabetical sort.

using System;

class Program
{
  static void Main(string[] args)
  {
    string[] cars = {"Volvo", "BMW", "Ford", "Mazda"};
    Array.Sort(cars);
    foreach (string i in cars)
    {
      Console.WriteLine(i);
    }
  }
}