Hi,
I have a base class Base_t and multiple derived classes from it (like Dog_t
and Cat_t, and so on).
I collect the base addresses of these objects in a vector.
By using this vector I then need to access the original objects.
Not just some virtual functions of the objects, but the complete original object.
How best to do this?
The following solution is IMO not that satisfactory.
Is there a better way, maybe in newer C++ standards like c++20? Something like:
auto& X = helper(pBase); // X will be of type Dog_t or Cat_t etc.
Thx
class Base_t { ...
class Dog_t : public Base_t { ...
class Cat_t : public Base_t { ...
...
enum Type_t { Unknown, Base, Dog, Cat };
struct Identity_t
{
Type_t Type;
union
{
Base_t* pBase;
Dog_t* pDog;
Cat_t* pCat;
};
Identity_t() : Type(Unknown) { pBase = nullptr; }
};
Identity_t Identity(Base_t* pBase)
{
Identity_t I;
if ((I.pDog = dynamic_cast<Dog_t*>(pBase))) { I.Type = Dog; return I; }
if ((I.pCat = dynamic_cast<Cat_t*>(pBase))) { I.Type = Cat; return I; }
return I;
}
// And using it like this:
// p is the address of a derived object, ie. Dog_t* or Cat_t*
auto I = Identity(p);
if (I.Type == Dog)
{ // use I.pDog to access it
auto& X = *I.pDog;
X.print();
}
else if (I.Type == Cat)
{ // use I.pCat to access it
auto& X = *I.pCat;
X.print();
}
...
// end of code
