The assert() will be triggered since mask will be 0.
The same problem comes up in other situations BTW. As well as the type of literal "0" being ambiguous, there's many similar situations that a C++ programmer should be aware of. e.g. what's the type of the literal "1" below, and does the assertion fail?unsigned long long mask = 1<<48; assert( mask == 0x1000000000000 );
I prefer self-documenting code and always use NULL. It is theoretical that NULL could be defined as something other than 0 but:
#1: It wouldn’t change the integrity of my code as long as I am always using NULL to check for invalid pointers as apposed to mixing between if ( ptr == NULL ) and if ( !ptr ).
#2: 0 is the only literal constant that is defined by the standard to be implicitly castable to a pointer of any kind, thus the idea that NULL could be something other than 0 is only theoretical, and anyone who ends up in such a situation brought it upon him- or her- self.