Do you know that? 33% like freelancing because no office dress code next

What is a null pointer?

There are times when it's necessary to have a pointer that doesn't point to anything. The
macro NULL, defined in <stddef.h>, has a value that's guaranteed to be different from any valid pointer. NULL
is a literal zero, possibly cast to  void* or  char*. Some people, notably C++ programmers, prefer to use 0 rather
than NULL.

You can't use an integer when a pointer is required. The exception is that a literal zero value can be used as
the null pointer. (It doesn't have to be a literal zero, but that's the only useful case. Any expression that can
be evaluated at compile time, and that is zero, will do. It's not good enough to have an integer variable that
might be zero at runtime.)