set class is used for the operation on sets having unique keys. A set class is declared as:
template <class Key, class Comp = less<Key>, class Allocator = allocator<Key>> class set
Types of set constructors:
Type-1: Empty set
explicit set(const Comp &cmpfn = Comp( ), const Allocator &a = Allocator( ) );
Type-2: set having same elements as obj.
set(const set<Key, Comp, Allocator> &obj);
Type-3: set having elements in the range i and j.
template <class InIter> set(InIter i, InIter j, const Comp &b = Comp( ), const Allocator &a = Allocator( ));
Types of set operators: ==, <, <=, !=, >, >=