@ is not printed.

Question

5.00/5 (1 vote)

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I am using following code.

namespace Null
{
    class Program
    {
        enum Fruits
        {
            @apple =-1,
            Apple = 1,
            Grapes = 2,
            Orange = 3,           
        };
        static void getfruit(Fruits f)
        {
            Console.WriteLine(f);
        }
        static void getfruit(Nullable<fruits> f = Fruits.@apple)
        {

            try { Console.WriteLine(f); }
            catch { Console.WriteLine("Null"); }         
        }
        static void Main(string[] args)
        {
           getfruit(Fruits.Apple);
           getfruit();
           Console.Read();
        }
    }
}

Output:
Apple
apple

Why is it not producing @apples as output?

Posted 30-Aug-10 9:53am

GD6882

Updated 30-Aug-10 10:38am

v3

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Comments

Toli Cuturicu 30-Aug-10 16:16pm

Reason for my vote of 5
Is this a test?

Henry Minute 30-Aug-10 17:17pm

That (@null) is what I would expect. See Chris Trelawney-Ross's answer for the explanation.

4 solutions

Solution 3

OK. Your code compiles now.

I am surprised to find that rather than throw a compile error, VS simply discards the @ so that your enum is compiled as if it was

enum Fruits
{
   apple = -1,
   Apple = 1,
   Grapes = 2,
   ...............
   ...............
}

which is why the @ doesn't print. As Dalek Dave said in his answer VS seems to be treating it as whitespace.

You can test that this is happening because when you try to use the enum in code, intellisense only shows the modified version.

Two suggestions:
1. If the @ is important test for 'apple' and

if (f == Fruits.apple)
{
  Console.WriteLine('@' + f);
}

2. Edit your question again (or ask a new question) describe what it is that you are trying to achieve. Someone may be able to offer an alternative.

Posted 30-Aug-10 11:01am

Henry Minute

Updated 30-Aug-10 11:02am

v2

Comments

GD6882 30-Aug-10 17:13pm

Nothing just stumbled accross this case.
Try this null is an reserved Keyword. I tried it as @null=-1, and it allowed me to declare it.
Funny :)

Toli Cuturicu 4-Sep-10 5:10am

Reason for my vote of 3
not quite so

Solution 1

enum may not have white spaces in it's name.
The @ is considered a non applicable whitespace character.

Posted 30-Aug-10 10:04am

Dalek Dave

Comments

GD6882 30-Aug-10 17:11pm

Thanks,
But @null=-1 is accepted. Why so since null as identifier is not allowed as it is resevered keyword.

Toli Cuturicu 4-Sep-10 5:08am

Reason for my vote of 2
false

Solution 2

The code that you have posted does not compile in either VS2008 nor VS2010.

What version are you using?

Did you cut and paste the code or just type it in? If you typed it, I would recommend that you edit your question and copy/paste your code in.

Posted 30-Aug-10 10:26am

Henry Minute

Comments

GD6882 30-Aug-10 16:35pm

class Program {
        enum Fruits {
            @apple = -1,
            Apple = 1,
            Grapes = 2,
            Orange = 3 };
        static void getfruit(Fruits f) {
            Console.WriteLine(f); } static void getfruit(Nullable<Fruits> f = Fruits.@apple) 
{ try 
{ 
Console.WriteLine(f); 
} 
catch 
{ Console.WriteLine("Null"); } } 
static void Main(string[] args) 
{ getfruit(Fruits.Apple); 
getfruit(); 
Console.Read(); } }

Try this

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Chris Trelawny-Ross · Accepted Answer · 2010-08-30T11:05:00

See C# Language Specification[^] ... '@' is not part of the identifier (in section 2.4.2 Identifiers):

"The prefix "@" enables the use of keywords as identifiers, which is useful when interfacing with other programming languages. The character @ is not actually part of the identifier, so the identifier might be seen in other languages as a normal identifier, without the prefix. An identifier with an @ prefix is called a verbatim identifier. Use of the @ prefix for identifiers that are not keywords is permitted, but strongly discouraged as a matter of style."

So, since the '@' is not part of the identifier, then it is reasonable that @myEnumValue.ToString() will not render the '@'.

@ is not printed.

4 solutions

Solution 4

Solution 3

Solution 1

Solution 2

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