#include <algorithm> int lexicographical_compare_3way( iterator start1, iterator end1, iterator start2, iterator end2 );
The lexicographical_compare_3way() function compares the first range, defined by [start1,end1) to the second range, defined by [start2,end2).
If the first range is lexicographically less than the second range, this function returns a negative number. If the first range is lexicographically greater than the second, a positive number is returned. Zero is returned if neither range is lexicographically greater than the other.
lexicographical_compare_3way() runs in linear time.