Thread: checking type of class

I don´t know if typeid works with polimorphism, but you could store a string in the class that says what it is

I'm not sure why you would need to know. If you are passing a base class pointer to some function you should probably be changing / setting things that are common members in the base class. I guess you could use typeid if you really wanted to but, imo, for the case you are describing it would be poor design.

I agree with MrWizard, but if you really need to, here are a couple ideas:

Code:

// Not a particularly good idea...
class base
{
   std::string type_;
public:
   base(std::string str) : type_(str) {}
   virtual std::string type() const;
};

class a : public base
{
public:
   a() : base("a") {}
...
};

// later on...
voif foo(base* x)
{
   if(x->type() == "a") ...
}

The other possibility is to dynamic_cast:

Code:

// A slightly better idea
template<typename T, typename U>
bool is_type(U* x)
{
   return (dynamic_cast<T*>(x) != 0);
}

// later on...
void foo(mammal* x)
{
   if(is_type<cat>(x)) ...
}

Again, you really shouldn't need to no in most cases, and there usually is a better was around.