What exactly is the array name in c?

Question

I am having a tough time understanding the type and use of the name of the array in C. It might seems a long post but please bear with me.

I understand that the foll

Answer 1

1. a and &a have the same values.How?

They have the same value but different types. Array objects have no padding between elements (before or after) so the address of the array and the address of the first element of the array are the same.

That is:

(void *) a == (void *) &a

2. What exactly it does int (*p)[3]; Declares a pointer to an array,i know this.But,how a pointer to an array is different from the pointer to the first element of the array and name of the array?

These are two different pointer types. Take for example, pointer arithmetic:

a + 1   /* address of the second element of the array */
&a + 1  /* address one past the last element of the array */

EDIT: due to popular demand I added below some information about conversion of arrays.

With three exceptions, in an expression an object of type array of T is converted to a value of type pointer to T pointing to the first element of the array. The exceptions are if the object is the operand of sizeof or & unary operator or if the object is a string literal initializing an array.

For example this statement:

printf("a:%d\t&a:%d\n", a, &a);

is actually equivalent to:

printf("a:%d\t&a:%d\n", &a[0], &a);

Also please note that d conversion specifier can only be use to print a signed integer; to print a pointer value you have to use p specifier (and the argument must be void *). So to do things correctly use:

printf("a:%p\t&a:%p\n", (void *) a, (void *) &a);

respectively:

printf("a:%p\t&a:%p\n", (void *) &a[0], (void *) &a);