Is there a nice way to assign std::minmax(a, b) to std::tie(a, b)?

Question

std::tie(a, b) = std::minmax(a, b);

I think this is intuitive code. Clean and understandable. Too bad it doesn\'t work as intended, as std::minmax temp

Answer 1

Sometimes, taking a step back and finding a different way pays off:

if (b < a)
    std::iter_swap(&a, &b);

That's concise and generally more efficient, certainly at least on par. Maybe pack it into its own function:

template 
void reorder(T& a, T& b)
noexcept(noexcept(b < a, void(), std::iter_swap(&a, &b))) {
    if (b < a)
        std::iter_swap(&a, &b);
}

I'm using std::iter_swap() so I don't have to use the using std::swap; swap(a, b) two-step for generality in pre-C++2a, which introduces customization point objects making that obsolete.