Why am I getting this 'enum' is not a class or a namespace error?

Question

I need call a method with this signature in my Manager class:

void createPlayer(Player& player, PlayerType& playerType);

I have a Player defined like so:

using namespace std;

enum PlayerType { FORWARD, DEFENSEMAN, GOALIE };

class Player {
  public:
    Player();
    void setType(PlayerType);
  private:
    PlayerType type;
};

This is how I try to call the method in main ...

#include "Player.h"
#include "Manager.h"

int main() {

  Manager manager;
  Player player;
  PlayerType t = PlayerType::FORWARD;
  manager.createPlayer(player, t);

  return 0;
}

... but it fails to compile with this error:

Main.cc: In function ‘int main()’:
Main.cc:12:18: error: ‘PlayerType’ is not a class or namespace

Any ideas? Note: I cannot change the signature of the createPlayer method.

possible duplicate of [How to using Enums in C++](http://stackoverflow.com/questions/12183008/how-to-using-enums-in-c) — Mooing Duck, Mar 06 '14 at 23:50
do not `using namespace std` in header files. It is bad practice. — Yakk - Adam Nevraumont, Mar 07 '14 at 00:08

score 11 · Accepted Answer · answered Mar 06 '14 at 23:30

enum doesn´t create a namespace.

Therefor PlayerType t = PlayerType::FORWARD; should be changed to:

PlayerType t = FORWARD;

Notice that c++11 introduce enum classes, which have a namespace. Beside this MSVC has an extension which treats (regular) enums like they have namespace. So your code should actually work with MSVC.

score 7 · Answer 2 · answered Mar 06 '14 at 23:33

Unfortunately enum by default doesn't create an enum namespace. So when declaring:

enum PlayerType { FORWARD, DEFENSEMAN, GOALIE };

you'll have to use it like this:

auto x = FORWARD;

Thankfully, though, C++11 introduced enum class or enum struct to solve this issue:

enum class PlayerType { FORWARD, DEFENSEMAN, GOALIE };

You'll then be able to access it like you did:

auto x = PlayerType::FORWARD;

score 1 · Answer 3 · answered Mar 06 '14 at 23:50

Your error seems to be in this line: PlayerType t = PlayerType::FORWARD;

As far as I know, the scope resolution operator (::) is not valid on regular C++98 enums unless your compiler supports them through non-standard extensions (like Visual Studio). Therefore you can't use it to reference an specific value from the enumerator.

Also, C++98 enums have the problem of polluting the namespace in which they are defined which can lead to name clash. Luckily C++11 solved this introducing the enum class. For more information check Stroustrup's FAQ: http://www.stroustrup.com/C++11FAQ.html#enum

score 0 · Answer 4 · edited Jun 02 '14 at 17:14

0

add a static function say getForward:

class Player {
  public:
    Player();
    void setType(PlayerType);
    static PlayerType getForward {
        return FORWARD;
    }
  private:
    PlayerType type;
};

Then use it in main:

manager.createPlayer(player, Player::getForward());

This should work.

edited Jun 02 '14 at 17:14

AMIC MING

6,306
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answered Jun 02 '14 at 16:56

Pete

1

Why am I getting this 'enum' is not a class or a namespace error?

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