Get min / max value of a static constexpr array at compile time

Question

Let's say I have an array of integers defined like that:

static constexpr int IntArray[] = {1, 5, 10, 12, 17}; 

Is there a way to get the minimum or maximum value at compile time?

Answer 1

Let's get the C++17 solution out of the way for future search-landers:

constexpr int IntArray[] = {1, 5, 10, 12, 17}; constexpr int min = *std::min_element(std::begin(IntArray), std::end(IntArray)); static_assert(min == 1); 

C++11 is more picky with constexpr functions, so we have to roll out a recursive algorithm. This one is a simple, linear one:

template <class T> constexpr T &constexpr_min(T &a, T &b) {     return a > b ? b : a; }  template <class T> constexpr T &arrayMin_impl(T *begin, T *end) {     return begin + 1 == end         ? *begin         : constexpr_min(*begin, arrayMin_impl(begin + 1, end)); }  template <class T, std::size_t N> constexpr T &arrayMin(T(&arr)[N]) {     return arrayMin_impl(arr, arr + N); }  constexpr int IntArray[] = {1, 5, 10, 12, 17}; constexpr int min = arrayMin(IntArray); 

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