What is the difference between 'int' and 'int?'. For example:
public int? GoalPR { get; set; } public int AnchorPR { get; set; } 
4 Answers
The int? is a nullable type, so the type that can be also null.
The main reason of introduction of this kind of types for value types, is fluent support for DataBase systems, where value: can be, can be absent and can be null.
There are actually 3 states.
So your code that interacts with the data received and sent to DB smoothly handles that kind of situations having possibility for its own value types assume null value too.
1 Comment
JBelter
Ah, ok that makes a lot more sense. Thank you.
Take a look at the documentation for Nullable<T>.
int? is just syntactic sugar for Nullable<int>
Comments
int? can be null.
int can't.
That's (pretty much) the only difference.
4 Comments
Lee
That's hardly the only difference - they are different sizes and reading/writing int values is atomic, while they aren't for nullable ints.
It'sNotALie.
@Lee For your first one: we're not using pointers. Second one: Sure is, unless you're using the value again, which is what most people do.
Lee
I don't see what pointers have to do with anything, and for the second point, reading/writing nullable ints is not atomic, so multiple threads updating an
int? field could see torn reads and writes. See this question for example.It'sNotALie.
@lee Why else would you need the size? Also, I know. However, when you're using ints most changes are something like
x = someOperations + x and so on. And if you aren't using Interlocked there then you have a problem.int? is nullable, int is not..
int?is anullable int, which allows the value to be null.intandint?is exactly the same as the difference betweenintandNullable<int>.int?is merely a short-hand forNullable<int>o_O