Standard C++ Library User Guide and Tutorial

while the merge will contain five. To form the merge, the function merge() can be used (see
Chapter 14: Merge Ordered Sequences). The arguments to this function exactly match those of the
set_union() function.
Set Difference
There are two forms of set difference. A simple set difference represents the elements in the first set
that are not contained in the second. A symmetric set difference is the union of the elements in the
first set that are not contained in the second, with the elements in the second that are not contained
in the first. These two values are constructed by the functions set_difference() and
set_symmetric_difference(), respectively. The use of these functions is similar to the use of the
set_union() function described earlier.
Other Generic Algorithms
Because sets are ordered and have constant iterators, a number of the generic functions described in
Chapters 13 and 14 either are not applicable to sets or are not particularly useful. However, the
following table gives a few of the functions that can be used in conjunction with the set data type.
Purpose Name Chapter / Section
Copy one sequence into another copy 13 (Copy One Sequence into Another
Sequence)
Find an element that matches a condition find_if 13 (Find an Element Satisfying a
Condition)
Find a subsequence within a set search 13 (Find a Subsequence within a Sequence)
Count number of elements that satisfy
condition
count_if 13 (Count the Number of Elements...)
Reduce set to a single value accumulate 13 (Reduce Sequence to a Single Value)
Execute function on each element for_each 13 (Apply a Function to All Elements in a
Collection)