...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
boost::algorithm::all_of_equal
// In header: <boost/algorithm/cxx11/all_of.hpp> template<typename Range, typename T> bool all_of_equal(const Range & r, const T & val);