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

Dereferencing a null pointer is undefined behavior. If you want to crash if the pointer is null, use an assert or something similar (and, depending on the defined behavior of your class, that can be a perfectly valid response - it's certainly better than continuing to run when people may be expecting something to have been done!).

Since the behavior of dereferencing a null pointer is undefined, it can do anything. Crash, corrupt memory, create a wormhole to an alternate dimension allowing the Elder Gods to come forth and devour all of mankind... anything. While bugs happen, depending upon undefined behavior is, by definition, a bug. So don't do it deliberately.