Checking for null before pointer usage

Question

Most people use pointers like this...

if ( p != NULL ) {
  DoWhateverWithP();
}

However, if the pointer is null for whatever reason, the functi

Answer 1

How about: a comment clarifying the intent? If the intent is "this can't happen", then perhaps an assert would be the right thing to do instead of the if statement.

On the other hand, if a null value is normal, perhaps an "else comment" explaining why we can skip the "then" step would be in order. Stevel McConnel has a good section in "Code Complete" about if/else statements, and how a missing else is a very common error (distracted, forgot it?).

Consequently, I usually put a comment in for a "no-op else", unless it is something of the form "if done, return/break".