Question

enum bool
{
    FALSE = 0,
    TRUE = 1
};

I’m wondering how to translate this in a modern C++ approach and if there is a well suited container for that; i know that the enum are not really that appreciated, but i can’t think about a real alternative in the C++ world.

What if would like to associate the execution of a particular method with a state?

---

Ok, this is the part where i will be more verbose.

I would like to stress the fact that i’m asking about structures symbolic constants and not about TRUE and FALSE, i’m not that “needy”.

Suppose that i have a structure that can represent several states with their own constants

enum semaphore
{
    GREEN = 0,
    ORANGE = 1,
    RED = 2
};

this is C code, now my question is about how to do the same in C++ if there is a better way.

My question continue when i ask about the possibility to do something like an automatic triggering when a change of state will occur, for example:

int main
{
   ...
   semaphore = 1;
   ...
}

and without any extra statements this has to trigger a method() just because the semaphore is now orange.

I hope that is more clear now.

Answer 1

What if would like to associate the execution of a particular method with a state?

I’m not sure I get your point, but maybe you mean something like this:

DEFINITION

Instead of this:

enum BOOL
{
  FALSE = 0,
  TRUE = 1
};

void executeOnlyWithTrue(BOOL b)
{
  if (b == TRUE)
  {
    RunParticularMethodOnlyNeededForTrueState();
  }
}

You do this:

class BOOL
{
public:
  virtual void  executeOnlyWithTrue() const {/*default does nothing*/} 
};

class FALSE : public BOOL
{  //no override, so using default executeOnlyWithTrue (BOOL's) 
};

class TRUE : public BOOL
{
public:
  virtual void  executeOnlyWithTrue() const
  {
    RunParticularMethodOnlyNeededForTrueState();
  }
};

USAGE

Instead of this:

const BOOL b = TRUE;
...
executeOnlyWithTrue(b)
...

You do this:

const BOOL& b = TRUE();
b.executeOnlyWithTrue();