Understanding C Templates with Non-Type Parameters

In C , templates provide a powerful mechanism for generic programming, allowing you to write code that operates on different data types at compile time. While type parameters are commonly used in templates, it's also possible to define non-type parameters.

Non-Type Parameters

Non-type parameters in templates refer to the ability to parameterize a template with:

• Integral constant expressions (e.g., unsigned int N in your example)
• Pointers
• References

Example: Integral Constant Expression Parameter

In your code, the template declares an integral constant expression parameter. This parameter represents a compile-time constant of type unsigned int. You can then use this parameter within the template as a constant value.

Template Without a Type Parameter

While templates typically require at least one type parameter, it's possible to create a template with only non-type parameters. In this case, the template is essentially a generic function that operates on the specified values specified by the non-type parameters.

Types of Non-Type Parameters

In addition to integral constant expressions, non-type parameters can include:

• Pointers, which can reference functions or objects with external linkage.
• References, which can reference variables with external linkage.

Default Parameters

Templates can also have default parameters, so it's not necessary to explicitly specify values for all non-type parameters. If not provided, the default value specified in the template declaration will be used.

Template Specialization

The syntax template is typically used to define an explicit specialization of a template for a particular set of parameters. In the provided example, it would not be a valid template specialization since it lacks any explicit parameter values.

Summary

Non-type parameters allow you to create templates that can be parameterized with various types of constants, pointers, and references, providing additional flexibility and control in your code design and implementation.