Intermediate C#
Q99 / 100

What is the difference between IEnumerable and IReadOnlyCollection in C#?

Correct! Well done.

Incorrect.

The correct answer is B) IEnumerable is forward-only lazy; IReadOnlyCollection adds Count and Contains, implying the collection is fully materialized

B

Correct Answer

IEnumerable is forward-only lazy; IReadOnlyCollection adds Count and Contains, implying the collection is fully materialized

Explanation

Prefer IReadOnlyCollection<T> in APIs when callers need Count without materializing. Use IEnumerable<T> only when lazy evaluation is intentional.

Progress
99/100