C is not C++ C compilers are leagues, elephants and donuts faster than C compilers. In C, internal guards are preferred and cause very little to no compilatio

C is not C++ C compilers are leagues, elephants and donuts faster than C compilers. In C, internal guards are preferred and cause very little to no compilation time hit. In C++, external are often preferred, especially in large files. Do not take C++ advice to apply to C. The best practices of both languages are very different.