Method which accepts both int[] and List<int>

Question

Question: Write a single method declaration which can accept both List<int> and int[]

My answer involved something like this:

void TestMethod(object param) // as object is the base class which can accept both int[] and List<int>

But that was not the intended answer, she said so.

Any ideas how that method signature would be ?

Answer 1

You can use IList<int> which both, int[] and List<int> implement:

void TestMethod(IList<int> ints)

On that way you can still use the indexer or the Count property( yes, an array has a Count property if you cast it to IList<T> or ICollection<T>). It's the greatest possible intersection between both types which allows fast access, using for-loops or other supported methods.

Note that some methods are not supported even if they can be called like Add, you'll get a NotSuportedException at runtime("Collection was of a fixed size") if you use it with an array.

Answer 2

This might be the right answer:

void TestMethod(IEnumerable<int> list)

Answer 3

Your method could be like this

private void SomeMethod(IEnumerable<int> values)