C++ template instantiation: Avoiding long switches

Question

I have a class depending on an integer template parameter. At one point in my program I want to use one instantiation of this template, depending on a value of this paramet

Answer 1

You could use a variadic template, maybe like this:

#include 
#include 

int main(int argc, char * argv[])
{
    if (argc != 2) { return EXIT_FAILURE; }

    handle_cases<1, 3, 4, 9, 11>(std::stoi(argv[1]));
}

Implementation:

template  struct IntList {};

void handle_cases(int, IntList<>) { /* "default case" */ }

template  void handle_cases(int i, IntList)
{
    if (I != i) { return handle_cases(i, IntList()); }

    Wrapper w;
    w.foo();
}

template  void handle_cases(int i)
{
    handle_cases(i, IntList());
}