NULL pointer is the same as deallocating it?

Question

I was working on a piece of code and I was attacked by a doubt: What happens to the memory allocated to a pointer if I assign NULL to that pointer?

For instance:

Answer 1

No, it will be lost to the process forever. You will have a memory leak. If you keep doing this, your program will eventually run out of memory!! To avoid this, delete the object when you no longer need it.

Often people will set the pointer to NULL after deleting it, so that other parts of the program can verify that the object has been deleted, and thereby avoid accessing or deleting it again.