C# Array Initialization on []

Question

So in C# you can define an array like so:

string[] Demo;
string[,] Demo;
string[,,] Demo;

What does the , represent?

possible duplicate of [What are the differences between a multidimensional array and an array of arrays in C#?](http://stackoverflow.com/questions/597720/what-are-the-differences-between-a-multidimensional-array-and-an-array-of-arrays) — Jeroen Vannevel, Aug 23 '15 at 18:24

score 5 · Accepted Answer · edited Aug 23 '15 at 18:31

5

The dimensions.

No comma: 1 dimension
1 comma: 2 dimensions
2 commas: 3 dimensions
and so on...

Learn more about multi-dimensional arrays on MSDN.

edited Aug 23 '15 at 18:31

Preston Guillot

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answered Aug 23 '15 at 18:21

Matías Fidemraizer

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Heinzi · Answer 2 · 2015-08-23T18:26:14.280

Multi-dimensional arrays.

The following example would declare a string array with two dimensions:

string[,] demo = new string[5, 3];

The [,] syntax is useful, for example, if you have a method taking a 2D array as a parameter:

void myMethod(string[,] some2Darray) { ... }

Note the difference between multi-dimensional arrays (e.g. string[,]), which are like a matrix:

+-+-+-+-+
| | | | |
+-+-+-+-+
| | | | |
+-+-+-+-+
| | | | |
+-+-+-+-+

and jagged arrays (e.g. string[][]), which are basically arrays of arrays:

+------------+
| +-+-+-+-+  |
| | | | | |  |
| +-+-+-+-+  |
+------------+
| +-+-+-+-+  |
| | | | | |  |
| +-+-+-+-+  |
+------------+
| +-+-+-+    |
| | | | |    |  <- possible in jagged arrays but not in multi-dimensional arrays
| +-+-+-+    |
+------------+

Reference:

Arrays (C# Programming Guide)

score 0 · Answer 3 · edited May 23 '17 at 10:26

0

These are multi-dimensional arrays.

The difference between this and array[][] as you might be used to is described here and here

edited May 23 '17 at 10:26

Community

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answered Aug 23 '15 at 18:21

James Webster

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C# Array Initialization on []

3 Answers3