binary search

cppreference std::binary_search

Possible implementation

See also the implementations in libstdc++ and libc++.

template<class ForwardIt, class T>
bool binary_search(ForwardIt first, ForwardIt last, const T& value)
{
    first = std::lower_bound(first, last, value);
    return (!(first == last) && !(value < *first));
}

cppreference std::lower_bound

cppreference std::upper_bound

stackoverflow lower_bound to perform binary search