What is the last valid index of an array declared as int a[10] in C++?

Options

  • A. 10
  • B. 9
  • C. 8
  • D. More than one of the above
  • E. None of the above

Correct Answer (Detailed Explanation is Below)

B. 9

Detailed Explanation

Answer: (B) 9

An array declared as int a[10] contains 10 elements.

Since C++ uses zero-based indexing, the indexes are:

0, 1, 2, 3, 4, 5, 6, 7, 8, 9

Therefore, the last valid index is 9.

A useful formula is:

Last index = number of elements − 1