GATE CS 2019 Q24 — Programming in C

To find the output of the given C program, let's trace the array elements and pointer arithmetic step-by-step:

1. Array Initialization: The array arr is initialized with the following elements and their corresponding 0-based indices:

   Index	0	1	2	3	4	5	6	7	8	9	10	11	12
   Value	1	2	3	4	5	6	7	8	9	0	1	2	5

2. Pointer Initialization: The pointer ip is initialized as:

   int *ip = arr + 4;

   In C, the array name arr decays to a pointer to its first element (&arr[0]). Therefore, arr + 4 points to the element at index 4, which is arr[4] (value 5).
3. Evaluating the Print Statement: The program prints ip[1]. Using the definition of array subscripting in C: $$ip[1] = *(ip + 1)$$ Substituting ip = arr + 4 into the equation: $$ip[1] = *((arr + 4) + 1) = *(arr + 5) = arr[5]$$ The value stored at arr[5] is 6.

Thus, the number displayed on execution of the program is 6.