Question

Which of the following returns a signed integer type on finding the difference between two pointers to elements in the same array?

(a) __cptrdiff__

(b) cptrdiff_t

(c) __ptrdiff__

(d) ptrdiff_t

I had been asked this question at a job interview.

My question is from Standard Definition in portion C Library of C

Answer 1

Correct option is (d) ptrdiff_t

To explain I would say: ptrdiff_t is used for pointer arithmetic and array indexing. Only pointers to elements of the same array may be subtracted from each other.