C++在两个头文件中包含一个类

Question

I have to get a project done for university but I can not figure out how it can be done.

The problem is that I want to allocate a Condition object (not a Pointer) in the GameHandler Class like in the example below, but I can not do this because I think of the included Condition.h in the Engine Class. So I am not able to include the Condition class twice. Am I wright?

What can I do to get a solution that works kind like my wrong example?

Thank you a lot!!!

Condition.h:

#ifndef CONDITION_h
#define CONDITION_h

class Condition
{
  enum Rank {FIRST, SECOND, THIRD};
  void doSomething();
};

#endif

Engine.h

#ifndef ENGINE_h
#define ENGINE_h

#include "Condition.h"

class Engine
{
  Condition::Rank getter();
};

#endif

But now I have a third Class which should look like this where I want to create a Condition Object (not a Pointer). How can this be done?

GameHandler.h

#ifndef GAMEHANDLER_h
#define GAMEHANDLER_h

#include "Condition.h"

class GameHandler
{
  Condition condition_;
  condition_.doSomething();
}

#endif

Answer 1

Using:

#ifndef GAMEHANDLER_h
#define GAMEHANDLER_h

/.../

#endif

Will prevent multiple inclusion, so it doesn't matter if you include your header multiple times

Answer 2

By default, class members are private in C++ (more about access specifiers here ). Try declaring them as public.

class Condition
{
public:
  enum Rank {FIRST, SECOND, THIRD};
  void doSomething();
};

Also, you cannot call a method within the declaration of a class, You'd have to do it inside a method (for example, the constructor), but the where will depend on what do you want to do.

class GameHandler
{
  Condition condition_;

public:
  GameHandler() {
    condition_.doSomething();
  }
}