Is there a more elegant solution (to a hopefully obvious problem) than
switch(variableInt)
{
case 0: tmpl<0>::foo(); break;
case 1: tmpl<1>::foo(); break;
// up to, say, 10
}
Clearly, this can only be defined in some range. I only found old topics around this, maybe some nice C++17 or C++20 feature that helps us out here?
What about something like this?
#include <utility>
template <std::size_t I>
int foo(int arg) {
return I * arg;
}
template<std::size_t ...Is>
auto get_foo(std::index_sequence<Is...>, int i) {
return *(std::initializer_list<int(*)(int)>{&foo<Is>...}.begin() + i);
}
int foo(std::size_t i, int arg) {
return get_foo(std::make_index_sequence<11>(), i)(arg);
}
Here's another solution that optimizes more nicely:
#include <utility>
template <std::size_t I>
int foo(int arg) {
return I * arg;
}
template<std::size_t ...Is>
auto foo(std::index_sequence<Is...>, int i, int arg) {
int ret;
((Is == i && (ret = foo<Is>(arg))), ...);
return ret;
}
int foo(std::size_t i, int arg) {
return foo(std::make_index_sequence<11>(), i, arg);
}