Standard C++ Library User Guide and Tutorial

set_union form union of two sets
set_intersection form intersection of two sets
set_difference form difference of two sets
set_symmetric_difference form symmetric difference of two sets
includes see if one set is a subset of another
Heap operations
Section Heap Operations
make_heap turn a sequence into a heap
push_heap add a new value to the heap
pop_heap remove largest value from the heap
sort_heap turn heap into sorted collection
Ordered collections can be created using the standard library in a variety of ways. For example:
The containers set, multiset, map and multimap are ordered collections by definition.
A list can be ordered by invoking the sort() member function.
A vector, deque or ordinary C++ array can be ordered by using one of the sorting algorithms
described later in this section.
Like the generic algorithms described in the previous section, the algorithms described here are
not specific to any particular container class. This means they can be used with a wide variety
of types. Many of them do, however, require the use of random-access iterators. For this reason
they are most easily used with vectors, deques, or ordinary arrays.
Obtaining the Sample Programs
Almost all the algorithms described in this section have two versions. The first version uses the
less than operator (operator <) for comparisons appropriate to the container element type. The
second, and more general, version uses an explicit comparison function object, which we will
write as Compare. This function object must be a binary predicate (see Section 3: Sorting
Algorithms). Since this argument is optional, we will write it within square brackets in the
description of the argument types.
A sequence is considered to be ordered if for every valid (that is, denotable) iterator i with a
denotable successor j, it is the case that the comparison Compare(*j, *i) is false. Note that this
does not necessarily imply that Compare(*i, *j) is true. It is assumed that the relation imposed
by Compare is transitive, and induces a total ordering on the values.
In the descriptions that follow, two values x and y are said to be equivalent if both Compare(x,