C++ Multisets are like sets, in that they are associative containers containing a sorted set of objects, but differ in that they allow duplicate objects.
| Multiset Constructors | default methods to allocate, copy, and deallocate multisets | 
| Multiset Operators | assign and compare multisets | 
| begin | returns an iterator to the beginning of the multiset | 
| clear | removes all elements from the multiset | 
| count | returns the number of elements matching a certain key | 
| empty | true if the multiset has no elements | 
| end | returns an iterator just past the last element of a multiset | 
| equal_range | returns iterators to the first and just past the last elements matching a specific key | 
| erase | removes elements from a multiset | 
| find | returns an iterator to specific elements | 
| insert | inserts items into a multiset | 
| key_comp | returns the function that compares keys | 
| lower_bound | returns an iterator to the first element greater than or equal to a certain value | 
| max_size | returns the maximum number of elements that the multiset can hold | 
| rbegin | returns a reverse_iterator to the end of the multiset | 
| rend | returns a reverse_iterator to the beginning of the multiset | 
| size | returns the number of items in the multiset | 
| swap | swap the contents of this multiset with another | 
| upper_bound | returns an iterator to the first element greater than a certain value | 
| value_comp | returns the function that compares values |