A.2.8. Set Algorithms for Sorted Sequences

The set algorithms implement general set operations on a sequence that is in sorted order. These algorithms are distinct from the library set container and should not be confused with operations on sets. Instead, these algorithms provide setlike behavior on an ordinary sequential container (vector, list, etc.) or other sequence, such as an input stream.

These algorithms process elements sequentially, requiring input iterators. With the exception of includes, they also take an output iterator denoting a destination. These algorithms return their dest iterator incremented to denote the element just after the last one that was written to dest.

Each algorithm is overloaded. The first version uses the < operator for the element type. The second uses a given comparison operation.

includes(beg, end, beg2, end2)
includes(beg, end, beg2, end2, comp)

Returns true if every element in the second sequence is contained in the input sequence. Returns false otherwise.

set_union(beg, end, beg2, end2, dest)
set_union(beg, end, beg2, end2, dest, comp)

Creates a sorted sequence of the elements that are in either sequence. Elements that are in both sequences occur in the output sequence only once. Stores the sequence in dest.

set_intersection(beg, end, beg2, end2, dest)
set_intersection(beg, end, beg2, end2, dest, comp)

Creates a sorted sequence of elements present in both sequences. Stores the sequence in dest.

set_difference(beg, end, beg2, end2, dest)
set_difference(beg, end, beg2, end2, dest, comp)

Creates a sorted sequence of elements present in the first sequence but not in the second.

set_symmetric_difference(beg, end, beg2, end2, dest)
set_symmetric_difference(beg, end, beg2, end2, dest, comp)

Creates a sorted sequence of elements present in either sequence but not in both.