Question { HP, 9884 }

How to implement call back functions ?

Answer

thru function pointer approach

Question { Verizon, 48705 }

what is the difference between
const char *p, char const *p, const char* const p

Answer

const char*p - p is pointer to the constant character i.e
value in that address location is constact

char const *p - same as above

const char* const p - p is the constant pointer which
points to the constant string, both value and address are
constants

Question { Adobe, 40139 }

What is the difference between char a[] = "string"; and
char *p = "string"; ?

Answer

we can not access a++ or a-- on array but we can do that in
pointers

array, address is constanct for that string, pointer is not
like that