C++: delete vs. free and performance

Question

1. Consider:

   char *p=NULL;
   free(p) // or
   delete p;
   

   What will happen if I use free and delete on p?

Answer 1

Answer 1: Both free(p) and delete p work fine with a NULL pointer.

Answer 2: Impossible to answer without seeing the slow parts of the code. You should profile the code! If you are using Linux I suggest using Callgrind (part of Valgrind) to find out what parts of the execution takes the most time.