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

a is a const pointer, whereas p is not
meaning 'a' will point to a fixed location (value of 'a' or 
address of *a can't change, remains fixed) - though 
contents of a can be changed (by way of accessing a[i])

we cannot assign a string to another but we can assign a 
char pointer to another char pointer.

char s[]; this allocate memory equal tosize of string
and char *s; holds the address of first charecter

hi im answering as far as i know , pls say ur feedback,,,(+_+)
Array:
for char array char a[]; no such array size is accepted by
the compiler. That is , it requires a fixed size for the
array  like: char a[20];

in this case the number of strings / characters it can hold
is only upto 20 while if it exceeds , the input strings get
truncated. [STATIC MEMORY ALLOCATION AND TRAVERSAL WITHIN
BOUNDS]

Pointer:
Whereas in case of pointers it is of DYNAMIC MEMORY type and
infinite storage when compared to Array. and predefinition ,
truncation are absent.
Also TRAVERSAL is easy.

Pointers are fine a cannot be changed p can be changed.

I have a doubt like is there any difference in memory
allocation.

I heard like a gets its memory in local stack and p gets in
data section.

I don get the clear explanation

char a[] will alocate the momery size of " string" word in 
other hand char *p will alocate the memory size of one 
character... or we can not move the data from one location 
to another location but with pointer we can do it...