How to find the max value of unknown integer type
c++
Solution
Use `std::numeric_limits<T>::max()`. Since C++11, this function is `constexpr` and thus evaluated at compile-time.
Problem
How can I find the maximal integer value of an unknown type? Is there something more efficient than this: ``` template<class T> T test(T i) { if (((T)-1) > 0) return -1; T max_neg = ~(1 << ((sizeof(T)*8)-1)); T all_ones = -1; T max_pos = all_ones & max_neg; return max_pos; } ```