#207 – Nullable Types

Because value types can’t normally represent null values, C# includes nullable types–types that can represent their normal range of values or represent a null value.

Any value type can be used as a nullable type by adding a trailing ? to the type name.

            int i = 12;   // regular int, can't be null

            int? j = 22;  // Nullable int, can be null
            j = null;     // Can also be null

Here are some other examples of nullable types.  In each case, we can set the variable’s value to null, which means that the variable doesn’t have a value that falls within the range of the corresponding type.

            double? r = null;
            bool? thisIsFalse = null;
            Mood? myMood = null;
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About Sean
Software developer in the Twin Cities area, passionate about software development and sailing.

5 Responses to #207 – Nullable Types

  1. Pingback: #566 – Implicit Conversions to Nullable Types « 2,000 Things You Should Know About C#

  2. Pingback: #581 – Boxing and Unboxing Nullable Types « 2,000 Things You Should Know About C#

  3. Pingback: #1,050 – Implicit Conversions between Nullable Types | 2,000 Things You Should Know About C#

  4. Pingback: #1,060 – Explicit Conversions between Nullable Types | 2,000 Things You Should Know About C#

  5. zzfima says:

    Hi
    I hink is good to add info, that nullable type is not reference type, but strict. Well answered there: http://stackoverflow.com/a/3149180/328829

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