C Programming: Pointer Arithmetic and Array Access Explained

The output of this program is:

'first_data = 2, second data = 5'

Explanation:

In this program, an integer array 'a' of size 5 is declared and initialized with values 1, 2, 3, 4, and 5. A pointer 'p' is also declared, which is initialized to the address of the next element after the end of 'a'.

Here, '&a' is the address of the entire array 'a', which is a pointer to an array of 5 integers. When we add 1 to this pointer, it moves to the next address after the end of 'a'. This means that 'p' now points to a memory location beyond the end of 'a'.

Next, we use '(a+1)' to access the second element of the array 'a', which has the value 2. We also use '(p-1)' to access the value stored in the memory location just before 'p', which happens to be the last element of 'a', with the value 5.

Therefore, the output of the program is 'first_data = 2, second data = 5'.