RTTI

RTTI(run-time type identification) ,like exceptions ,depends on type information residing in the virtual function table. If you try to use RTTI on a class that has no virtual functions, you will get unexpected results.

for example:

//C24RTTIWithoutPolymorphism.cpp
#include <cassert>
#include <typeinfo>
#include <iostream>
using namespace std;

class X {
 int i;
public:
 // ...
};

class Y : public X {
  int j;
public:
 // ...
};

int main() {
  X* xp = new Y;
  // the two below condition is true;
  assert(typeid(*xp) == typeid(X));
  assert(typeid(*xp) != typeid(Y));
  cin.get();
}

So  RTTI is intended for use only with polymorphic class. Without virtual function table, the typeid() will not work;