Arrays

Initializing Arrays

C# provides simple and straightforward ways to initialize arrays at declaration time by enclosing the initial values in curly braces ({}). The following examples show different ways to initialize different kinds of arrays.

Note   If you do not initialize an array at the time of declaration, the array members are automatically initialized to the default initial value for the array type. Also, if you declare the array as a field of a type, it will be set to the default value null when you instantiate the type.

Single-Dimensional Array

int[] numbers = new int[5] {1, 2, 3, 4, 5};
string[] names = new string[3] {"Matt", "Joanne", "Robert"};

You can omit the size of the array, like this:

int[] numbers = new int[] {1, 2, 3, 4, 5};
string[] names = new string[] {"Matt", "Joanne", "Robert"};

You can also omit the new operator if an initializer is provided, like this:

int[] numbers = {1, 2, 3, 4, 5};
string[] names = {"Matt", "Joanne", "Robert"};

Multidimensional Array

int[,] numbers = new int[3, 2] { {1, 2}, {3, 4}, {5, 6} };
string[,] siblings = new string[2, 2] { {"Mike","Amy"}, {"Mary","Albert"} };

You can omit the size of the array, like this:

int[,] numbers = new int[,] { {1, 2}, {3, 4}, {5, 6} };
string[,] siblings = new string[,] { {"Mike","Amy"}, {"Mary","Albert"} };

You can also omit the new operator if an initializer is provided, like this:

int[,] numbers = { {1, 2}, {3, 4}, {5, 6} };
string[,] siblings = { {"Mike", "Amy"}, {"Mary", "Albert"} };

Jagged Array (Array-of-Arrays)

You can initialize jagged arrays like this example:

int[][] numbers = new int[2][] { new int[] {2,3,4}, new int[] {5,6,7,8,9} };

You can also omit the size of the first array, like this:

int[][] numbers = new int[][] { new int[] {2,3,4}, new int[] {5,6,7,8,9} };

-or-

int[][] numbers = { new int[] {2,3,4}, new int[] {5,6,7,8,9} };

Notice that there is no initialization syntax for the elements of a jagged array.

Accessing Array Members

Accessing array members is straightforward and similar to how you access array members in C/C++. For example, the following code creates an array called numbers and then assigns a 5 to the fifth element of the array: