Defining Concepts
Explore how to define your own concepts in C++20 to enhance template programming and enforce type safety. Understand the syntax for concept definitions, how to use compile-time predicates and logical combinations, and apply practical examples like Integral and SignedIntegral concepts to improve your code.
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When the concept you are looking for is not one of the predefined concepts in C++20, you must define your own concept. In this section, I will define a few concepts which will be distinguishable from the predefined concepts through the use of CamelCase syntax. Consequently, my concept for a signed integral is named SignedIntegral, whereas the C++ standard concept goes by the name signed_integral.
The syntax for defining a concept is straightforward:
A concept definition starts with the keyword template and has a template parameter list. The second line is more interesting. It uses the keyword concept followed by the concept name and the constraint expression.
A constraint-expression can either be:
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A logical combination of other concepts ...