Placeholder Syntax
Explore how placeholder syntax evolves in modern C++, from unconstrained auto in C++11 to constrained concepts in C++20. Understand how generic lambdas become function templates and how concepts enforce type safety and consistency in templates, making generic programming simpler and more reliable.
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With auto, C++11 has unconstrained placeholders. We can use concepts in C++20 as constrained placeholders. Decisive quantum leap does not look so thrilling at the first glimpse. C++ templates will become easy to use C++ features.
According to our definition, C++98 is not a consistent language. By consistent, we mean that you have to apply a few rules to derived C++ syntax from it. C++11 is something in between. For example, we have consistent rules like initializing all with curly braces (see { } - Initialization). Of course, even C++14 has a lot of features where we miss a consistent principle. One of the favorites is the generalized lambda function. ...