class constants

**subdene** · 01-25-2003

Hi i'm trying to create a constant variable from within my class, but i just get the error

[C++ Error] Test.h(40): E2233 Cannot initialize a class member here

Do you have to declare 2d arrays differently from within the class?

Code:

  static const char Test[3][20] = {{"Test1"}, {"Test2"}, {"Test3"}};

Thanks.

stovellp · 01-25-2003

You cant initialise a variable inside a class.
I'm not sure, but I think you'd have to do it in the constructor.

Code:

class myClass
   {
   public:
      myClass();
      const int Height;
   };

myClass::myClass()
   {
   Height = 67;
   }

But if its a static variable, you define it outside the class, like:

Code:

const char myClass::Test[3][20] = {{"Test1"}, {"Test2"}, {"Test3"}};

**Sang-drax** · 01-25-2003

Originally posted by stovellp
You cant initialise a variable inside a class.

Yes, static const variables can be.

Code:

//Valid C++
class A
{
  static const int Test  = 1;
};

I'm not sure why arrays can't be initialized the same way, though.

**Polymorphic OOP** · 01-25-2003

Only const integers can be done like that sang-drax, nothing else.

**Sang-drax** · 01-25-2003

Yes, but why are only integral basic data types allowed?
I see no reason.

**Polymorphic OOP** · 01-25-2003

I wonder that same thing. Not even floating point types can be initialized in a class definition. There's probably some logical reason why they didn't, but I honestly can't think of one.

**subdene** · 01-26-2003

Hi all, thanks for your replies. I've just had to make the 2d array global, thats the only way i've managed to implement the class.

**Cela** · 01-26-2003

>>I've just had to make the 2d array global, thats the only way i've managed to implement the class.
Initialize the array just like you do member functions, the declaration is in the class and the definition is outside of the class with named scoping.

Code:

class test {
  static const char Test[3][20];
  ...
};

const char test::Test[3][20] = {"Test1", "Test2", "Test3"};

**subdene** · 01-26-2003

erm.... interesting. I'll have a go at that, thanks cela.

stovellp · 01-26-2003

Isn't that what I said in the first place?

**Cela** · 01-26-2003

>>Isn't that what I said in the first place?
Yep, but important concepts are best repeated. :-)

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