C++11 introduced parameter packs to provide a safer way to pass an undefined number of parameters to functions instead of relying on variadic functions.While packs are a useful feature, and since C++17 it’s so easy to use them in fold expressions, extracting a specific element of a pack is somewhat cumbersome.You either have to rely on some standard functions not made for the purpose or use “awkward boolean expression crafting or recursive templates”. None of them is unbearable, but it might be ...