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This article mainly introduces the relevant knowledge of what the single question mark and double question mark of C# have, the content is detailed and easy to understand, the operation is simple and fast, and it has certain reference value. I believe that you will gain something after reading this article on the role of single question mark and double question mark of C#. Let's take a look.

C # single question mark? With a double question mark?

? The single question mark is used for null assignment to int, double, bool and other data types that cannot be directly assigned to null, which means that the data type is of Nullable type.

Int? I = 3

Equivalent to:

Nullable I = new Nullable (3); int I; / / default 0int? Ii; / / default null

?? The double question mark is used to determine that a variable returns a specified value when it is null.

What is C #? C # is a simple, general-purpose, object-oriented programming language developed by Microsoft Microsoft. It inherits the powerful functions of C # and C++, and removes some of their complex features. C # combines the simple visual operation of VB and the high running efficiency of C++, and becomes the preferred language for .NET development because of its strong operation ability, elegant syntax style, innovative language features and convenient component-oriented programming. However, it is not suitable for writing code that is time-critical or very high-performance, because C# lacks the key functionality required by extremely high-performance applications.

This is the end of the article on "what is the function of single question mark and double question mark of C#". Thank you for your reading! I believe that everyone has a certain understanding of the knowledge of "what is the function of single question mark and double question mark of C#". If you still want to learn more knowledge, you are welcome to follow the industry information channel.

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