How do I declare a 2D array of Enum in C#?

Question

I am switching from Java to C# and I am wondering if this is possible? What I want to do is create a two dimensional array of the type Enum {north, south, east, west}. That way I can call map[1,2].north to find out if that cell on the map has a north wall or not.

Sorry for the crude code, I do not have access to my computer at the moment, so I am being a bit abstract.

Since you're coming from Java, you might want to know that `enums` in C# are [quite a bit weaker](https://stackoverflow.com/a/1376455/3927). — Rodrick Chapman, Aug 17 '17 at 20:14

Dmitry · Accepted Answer · 2017-08-17T20:22:38.193

3

For the enum:

enum Dirs { North, South, East, West }

Just declare an array as:

Dirs[,] dirs = new Dirs[10, 10];

If you need each cell to be able to have several walls, mark the enum with the [Flags] attribute and make the values to be powers of 2:

[Flags]
enum Dirs { North = 1 << 0, South = 1 << 1, East = 1 << 2, West = 1 << 3 }

Thus you'll be able to set, for instance:

dirs[1, 2] = Dirs.North | Dirs.East;

And as @Scott Chamberlain mentioned in his comment - to check a direction you can do:

bool hasNorthWall = dirs[1, 2].HasFlag(Dirs.North);

edited Aug 17 '17 at 20:22

answered Aug 17 '17 at 19:15

Dmitry

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2

The `Flags` attribute does not change the values of the enum members. If you use it, you need to explicitly set the values to be powers of 2, otherwise you'll end up with some undesired behavior. – Kyle Aug 17 '17 at 19:20
1

To be complete, to check a direction you can do `var hasNorthWall = dirs[1,2].HasFlag(Dirs.North);` – Scott Chamberlain Aug 17 '17 at 20:00
@ScottChamberlain Added to the answer, Thank you. – Dmitry Aug 17 '17 at 20:09
Another tip useful tip. When you need to make your powers of 2 for your flags, just use the left shift operator `[Flags] enum Dirs { North = 1<<0, South = 1<<1, East = 1<<2, West = 1<<3 }`. It makes it a lot easier to read when you start getting in to enums that use a lot of possible flag values, for example `SomeFlag = 1048576` vs `SomeFlag = 1<<20`. – Scott Chamberlain Aug 17 '17 at 20:12
@ScottChamberlain Well, I agree, it makes a big sense for guys that don't remember all powers of 2 up to 16 bits at least. :p – Dmitry Aug 17 '17 at 20:20
Hmm, I am starting to wonder if Enums don't work the way I think they do... Ultimately, what I want is a two dimensional array called map. Each cell (i am imagining it like a spreadsheet) needs to contain 6 values, north wall, south wall, east wall, west wall, floor and ceiling. These values should be integers, because when north wall = 1 it would be a standard stone wall, but if it = 2 then it could be a different texture. I am thinking I should just go ahead and create an object called "Room" give it these six integers as private variables, do the get/sets, and make an array from that. – Lame Brain Aug 17 '17 at 21:52

Daniel Forero · Answer 2 · 2017-08-17T19:18:26.780

0

try that:

private EnumName[,] arrayName;

edited Aug 17 '17 at 19:18

answered Aug 17 '17 at 19:14

Daniel Forero

95
6

score 0 · Answer 3 · answered Aug 17 '17 at 19:19

This is how you declare and test for walls using an enum.

namespace ConsoleApplication1
{
    [Flags]
    enum Wall
    {
        North = 1,
        South = 2,
        East  = 4,
        West  = 8
    }
    static class Program
    {
        static void Main(string[] args)
        {
            int grid = 10;
            var map=new Wall[grid, grid];
            // fill in values here ...
            if(map[1, 2].HasFlag(Wall.North))
            {
                // cell (2, 3) has a wall in the north direction
            }
        }
    }
}

How do I declare a 2D array of Enum in C#?

3 Answers3