#include <set>
  set operator=(const set& c2);
  bool operator==(const set& c1, const set& c2);
  bool operator!=(const set& c1, const set& c2);
  bool operator<(const set& c1, const set& c2);
  bool operator>(const set& c1, const set& c2);
  bool operator<=(const set& c1, const set& c2);
  bool operator>=(const set& c1, const set& c2);

All of the C++ containers can be compared and assigned with the standard comparison operators: ==, !=, <=, >=, <, >, and =. Performing a comparison or assigning one set to another takes linear time.

Two sets are equal if:

1. Their size is the same, and
2. Each member in location i in one set is equal to the the member in location i in the other set.

Comparisons among sets are done lexicographically.