Static Enumerated Variables

[seanc91]

I have a class:


class aCard
{
public:
SUIT suitType;
CARD cardType;
static SUIT suitCount;
static CARD cardCount;
void print();
aCard();
};



Where CARD and SUIT are enumerated types.

However, when I compile, I get these compile errors on MS Visual Studio Exp. 2008.


1>DeckOfCards.obj : error LNK2001: unresolved external symbol "public: static enum CARD aCard::cardCount" (?cardCount@aCard@@2W4CARD@@A)
1>DeckOfCards.obj : error LNK2001: unresolved external symbol "public: static enum SUIT aCard::suitCount" (?suitCount@aCard@@2W4SUIT@@A)
1>C:\Documents and Settings\Sean\My Documents\Visual Studio 2008\Projects\DeckOfCards\Debug\DeckOfCards.exe : fatal error LNK1120: 2 unresolved externals



I have no clue what is going on here, but I assume there is something to do with using an enumerated type as a type of static variable, can anyone help me on this?

[Plasmator]

This has nothing to do with enums, actually. You must define your static members outside of your class (in your c/cpp file). For example:

Whatever.h

struct Whatever
{
static int i;
};
Whatever.cpp

#include "Whatever.h"

int Whatever::i;

[seanc91]

This has nothing to do with enums, actually. You must define your static members outside of your class (in your c/cpp file). For example:

Whatever.h

struct Whatever
{
static int i;
};
Whatever.cpp

#include "Whatever.h"

int Whatever::i;


But I can have normal static variables inside the class, as it is now. I was under the impression that that was legal, and the point of static variables (so that in this case, all "aCards" had acess to suitCount and cardCount).

Eg.

class aCard
{
public:
SUIT suitType;
CARD cardType;
static int test;
SUIT suitCount;
CARD cardCount;
void print();
aCard();
};


Perhaps I'm misinterpreting what you're trying to say?

[Plasmator]

Perhaps I'm misinterpreting what you're trying to say? Look at the example that I posted. You still keep your data in the class; the only thing that's changed is that you have to go out of your way and define it in a compilation unit.

[seanc91]

I'm not sure this is right, its giving me a tonne of compile errors:

class.h


#include "stdafx.h"

#include "string"
#include <iomanip>
#include <iostream>

enum SUIT{DIAMONDS,SPADES,HEARTS,CLUBS};
enum CARD{ACE,KING,QUEEN,JACK,TEN,NINE,EIGHT,SEVEN,SIX,FIVE,FOUR,THREE,TWO};

struct test
{
static SUIT suitCount;
static CARD cardCount;
}


And then in my .cpp


class aCard
{
public:
SUIT suitType;
CARD cardType;


SUIT class::suitCount;
CARD class::cardCount;
void print();
aCard();
};


I'm guessing this isnt right. What am I doing wrong?

[Plasmator]

I'm not sure this is right, its giving me a tonne of compile errors:

class.h


#include "stdafx.h"

#include "string"
#include <iomanip>
#include <iostream>

enum SUIT{DIAMONDS,SPADES,HEARTS,CLUBS};
enum CARD{ACE,KING,QUEEN,JACK,TEN,NINE,EIGHT,SEVEN,SIX,FIVE,FOUR,THREE,TWO};

struct test
{
static SUIT suitCount;
static CARD cardCount;
}


And then in my .cpp


class aCard
{
public:
SUIT suitType;
CARD cardType;


SUIT class::suitCount;
CARD class::cardCount;
void print();
aCard();
};


I'm guessing this isnt right. What am I doing wrong?
This is what your header/source file should look like (more or less):
[NOTE: modify where necessary]

Header:

#ifndef <...> //include guard
#define <...>

#include <your headers>

//If I were you I'd put these in a separate namespace...
enum SUIT
{
<defs>
};

enum CARD
{
<defs>
};

class aCard
{
public:
SUIT suitType;
CARD cardType;

static SUIT suitCount; //You sure these should be enums?
static CARD cardCount; //Same with this...

void print();
aCard();
};
#endif


Source file:

#include "your header"

SUIT aCard::suitCount; //default constructed
CARD aCard::cardCount;

//<aCard function (+ctor, etc.) implementations go here...>

[Paul McKenzie]

I'm not sure this is right, its giving me a tonne of compile errors:

// cardsuit.h
#ifndef CARDSUIT_H
#define CARDSUIT_H
enum SUIT{DIAMONDS,SPADES,HEARTS,CLUBS};
enum CARD{ACE,KING,QUEEN,JACK,TEN,NINE,EIGHT,SEVEN,SIX,FIVE,FOUR,THREE,TWO};

struct test
{
static SUIT suitCount;
static CARD cardCount;
};
#endif


#include "cardsuit.h"
class aCard
{
public:
SUIT suitType;
CARD cardType;
void print();
aCard();
};

SUIT test::suitCount = 0;
CARD test::cardCount = 0;
I'm guessing this isnt right. What am I doing wrong?

http://www.parashift.com/c++-faq-lite/index.html
http://www.parashift.com/c++-faq-lite/ctors.html#faq-10.10

Regards,

Paul McKenzie

[seanc91]

Okay thanks guys, I got it. Thanks for the help.