1. Explain null pointer?

There are times when it's necessary to have a pointer that doesn't point to anything. The macro NULL, defined in , 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.

2. Explain void pointer?

A void pointer is a C convention for "a raw address." The compiler has no idea what type of object a void pointer "really points to." If you write
int *ip;
ip points to an int. If you write
void *p;
p doesn't point to a void!