If you declare int data[10], what is the index of the last element?

• A. data[9]
• B. data[10]
• C. data[8]
• D. data[0]

Answer: (A)

Arrays use zero-based indexing, meaning the first element is at index 0. If you declare int data[10], you’ve created 10 elements with indices 0 through 9. The last element is therefore data[9]. Accessing data[10] would go past the end (out of bounds), data[8] would be the second-to-last, and data[0] is the first.