The simplest way to say this is that metaprogramming is a technique that creates a code by using a code. Implementing metaprogramming, we write a computer program that manipulates the other programs and treats them as its data. In addition, templates are a compile-time mechanism in C++ that is Turing-complete, which means any computation expressible by a computer program can be computed, in some form, by a template metaprogram before runtime. It also uses recursion a lot and has immutable variables. So, in metaprogramming, we create code that will run when the code is compiled.
To start our discussion on metaprogramming, let's go back to the era when the ANSI C programming language was a popular language. For simplicity, we used the C preprocessor by creating a macro. The C parameterized macro is also known as metafunctions, and is one of the examples of metaprogramming. Consider the following parameterized macro:
#define...