Coding Bolt

Whether you are a beginner or not in C# you need to know the default values of primitive types when writing software. These values serve as a foundation for variable initialization and can prevent unexpected behaviors in your applications.

What are Primitive Types?

Primitive types, are the basic data types provided by a programming language. In C#, these types are structures and are value types, meaning they hold the data directly rather than a reference to the data. String and object are not primitive types.

Default Values

When you declare a variable of a primitive type without initializing it, .NET automatically assigns it a default value. Here’s a breakdown of the default values for common primitive types:

1. Integral Types
   • byte: Default value is 0.
   • sbyte: Default value is 0.
   • ushort: Default value is 0.
   • short: Default value is 0.
   • uint: Default value is 0.
   • int: Default value is 0.
   • ulong: Default value is 0.
   • long: Default value is 0.
   • char: Default value is '\0' (U+0000).
2. Floating-Point Types
   • float: Default value is 0.0f.
   • double: Default value is 0.0d.
   • decimal: Default value is 0.0m.
3. Boolean Type
   • bool: Default value is false.
4. DateTime Types
   • DateTime: Default value is DateTime.MinValue (01/01/0001 00:00:00).
   • DateOnly (Introduced in .NET 6): Default value is DateOnly.MinValue (01/01/0001).
   • TimeOnly (Introduced in .NET 6): Default value is TimeOnly.MinValue (00:00:00.0000000).
5. Reference Types
   • string and other reference types (like classes): Default value is null.

Conclusion

Default values in .NET provide a safety net for developers, ensuring that uninitialized variables of primitive types have a predictable value. By understanding these defaults, you can write more robust and predictable .NET applications.

*We will talk about Nullable Reference Types (a feature that if enabled, changes the way reference types work in C#) in a future blog post.