Item 38. Object Identity

Difficulty: 5

"Who am I, really?" This problem addresses how to decide whether two pointers really refer to the same object.

The "this != &other" test (illustrated below) is a common coding practice intended to prevent self-assignment. Is the condition necessary and/or sufficient to accomplish this? Why or why not? If not, how would you fix it?

T& T::operator=( const T& other ) 


{


  if( this != &other )    // the test in question


  {


    // ...


  }


  return *this;


}

Remember to distinguish between "protecting against Murphy versus protecting against Machiavelli"梩hat is, protecting against things going wrong on their own versus a malicious programmer going to great lengths trying to break your code.