What is the purpose of a question mark after a type (for example: int? myVariable)?

Question

Typically the main use of the question mark is for the conditional, x ? \"yes\" : \"no\".

But I have seen another use for it but can\'t find an explanat

Answer 1

To add on to the answers above, here is a code sample

struct Test
{
    int something;
}
struct NullableTest
{
    int something;
}
class Example
{
    public void Demo()
    {
        Test t = new Test();
        t = null;

        NullableTest? t2 = new NullableTest();
        t2 = null;
    }
}

This would give a compilation error:

Error 12 Cannot convert null to 'Test' because it is a non-nullable value type

Notice that there is no compilation error for NullableTest. (note the ? in the declaration of t2)