What does private short? units; mean?

[Mr Flibble]

I have this in some sample code

private short? units;

What does the '?' mean? I've only seen '?' as an operator.

[Göran Andersson]

That is the short form of a Nullable type. It's the same as:

private Nullable<shortunits;

It's a Nullable structure that contains a short value and a flag that
determines if the structure contains a valid value or not. The variable
can be assigned a null value:

units = null;

Or a short value:

units = 42;

The HasValue property determines if the structure contains a valid value:

if (units.HasValue) {
Console.Write(units.Value);
} else {
Console.Write("n/a");
}

Mr Flibble wrote:

I have this in some sample code

private short? units;

What does the '?' mean? I've only seen '?' as an operator.

[Mr Flibble]

* Mr Flibble wrote:

I have this in some sample code

private short? units;

What does the '?' mean? I've only seen '?' as an operator.

OK it's the new C# 2.0 NullableTypes thingy ma-jig.

[Jon Skeet [C# MVP]]

Mr Flibble <mr********@flibbyly.wobbly.n.etwrote:

* Mr Flibble wrote:

I have this in some sample code

private short? units;

What does the '?' mean? I've only seen '?' as an operator.

OK it's the new C# 2.0 NullableTypes thingy ma-jig.

For more on this, see
http://www.pobox.com/~skeet/csharp/c.../nullable.html

--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
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