the code below prints val2
on both f()
calls. What would be a proper way to execute specific branch in f()
based on enum value ?
enum class E
{
val1,
val2
};
using val1_t = std::integral_constant<E, E::val1>;
using val2_t = std::integral_constant<E, E::val2>;
template <typename T>
void f(T t)
{
if constexpr (std::is_same_v<T, val1_t>)
{
std::cerr << "val1\n";
}
else
{
std::cerr << "val2\n";
}
}
int main()
{
f(E::val1);
f(E::val2);
}
If you move the enum into the template parameter, then you could use
template <E val>
void f()
{
if constexpr (val == E::val1)
{
std::cerr << "val1\n";
}
else
{
std::cerr << "val2\n";
}
}
And you would use it like
int main()
{
f<E::val1>();
f<E::val2>();
}