Originally Posted by rpittala
PLEASE EXPLAIN ME SOME MORE POINTS ABOUT THE DOUBLE POINTER, OTHER THAN THE ABOVE CODE AND I AM EXPECTING THE ANSWERS WITH CODE EXAMPLES
That sounds like a homework assignment from an incompetent instructor. If so, please don't ask us to do your homework, and you have my sympathies regarding your instructor.
If it isn't homework, it is still a stupid question, especially together with the "advantage of" viewpoint from the thread title.
C allows whatever level of pointer indirection you choose to code. You should use two levels whenever that is appropriate to the problem. A good instructor should think of problems that cause the specific technique being taught at the moment to be appropriate. A student should practice finding the techniques that fit a specified problem, not finding the problems that fit a specified technique.