This is EXACTLY the wrong place to use dynamic_cast. You should be using polymorphism. Each of the Animal classes should have a virtual function, say, process and here you should just call animal->process().
class Animal { virtual void Process() = 0;}class Cat : public Animal { void Process() { std::cout << " I am a tiny cat"; }}class Bear : public Animal { void Process() { std::cout << "I am a big bear"; }}void func(Animal * animal) { if (animal != nullptr) { animal->Process(); }}Other problems.
What if animal is a Dog, but due to a bug animal_type says its a Cat?
There are times when static_cast is necessary, and if possible use it instead of dynamic_cast. Dynamic cast has the additional performance cost that static cast does not. For this, you need to be sure you know the type that is coming in, since static_cast is more unsafe.
At the very least, animal_type should be a member of Animal.