Self class verification in C++

gistfile1.cpp

#include <stdlib.h>
#include <iostream>

class ChildA;
class ChildB;

class Base {
public:
  bool isChildA ();
  bool isChildB (); 
  virtual void hoge () {
  }
};

class ChildA : public Base{
};

class ChildB : public Base {
};

bool Base::isChildA () {
  return (NULL != dynamic_cast <ChildA *> (this));
}    
bool Base::isChildB () {
  return (NULL != dynamic_cast <ChildB *> (this));
}    

int main () {
  Base *a = new ChildA ();
  Base *b = new ChildB ();
  std::cout << "a:" <<  a->isChildA () << "," << a->isChildB () << std::endl;
  std::cout << "b:" <<  b->isChildA () << "," << b->isChildB () << std::endl;
}

output

a:1,0
b:0,1

env

• Darwin nexus 11.4.2 Darwin Kernel Version 11.4.2: Thu Aug 23 16:25:48 PDT 2012; root:xnu-1699.32.7~1/RELEASE_X86_64 x86_64
• Apple clang version 4.1 (tags/Apple/clang-421.11.65) (based on LLVM 3.1svn)