>plz explain me with syntax "how to pass pointer to a function or pointers to a function "
For each level of indirection in the function argument list, add an asterisk. If the argument isn't already a pointer of the same type as the argument list, dereference or add & as necessary.

>plz tell me if there any big tutorial which can solve my problem providing a deep knowledge about it
http://pweb.netcom.com/~tjensen/ptr/pointers.htm

>what is incorrect int following program.
A lot, actually. First and foremost you forgot to include stdlib.h, an error that the casting of malloc's return value hid and is a good example of why you don't cast the return of malloc. Second, you don't provide a prototype for func even though the definition is after the first call. a is a pointer to a pointer to int yet func expects a pointer to int so that's a type mismatch, you test for null pointers after dereferencing the allocated memory so the damage would already have been done by that point. All in all, the code could be improved greatly, but I'll leave that to you after you look at the link I gave you.