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std::set_union

From cppreference.com
 
 
 
Defined in header <algorithm>
template< class InputIterator1, class InputIterator2, class OutputIterator >

OutputIterator set_union( InputIterator1 first1, InputIterator1 last1,
                          InputIterator2 first2, InputIterator2 last2,

                          OutputIterator d_first );
(1)
template< class InputIterator1, class InputIterator2,

          class OutputIterator, class Compare >
OutputIterator set_union( InputIterator1 first1, InputIterator1 last1,
                          InputIterator2 first2, InputIterator2 last2,

                          OutputIterator d_first, Compare comp );
(2)

Constructs a sorted range beginning at d_first consisting of all elements present in one or both sorted ranges [first1, last1) and [first2, last2). The first version expects both input ranges to be sorted with operator<, the second version expects them to be sorted with the given comparison function comp. If some element is found m times in [first1, last1) and n times in [first2, last2), then all m elements will be copied from [first1, last1) to d_first, preserving order, and then exactly std::max(n-m, 0) elements will be copied from [first2, last2) to d_first, also preserving order. The resulting range cannot overlap with either of the input ranges.

Contents

[edit] Parameters

first1, last1 - the first input sorted range
first2, last2 - the second input sorted range
comp - comparison function which returns ​true if the first argument is less than the second.

The signature of the comparison function should be equivalent to the following:

bool cmp(const Type1 &a, const Type2 &b);

The signature does not need to have const &, but the function must not modify the objects passed to it.
The types  Type1 and  Type2 must be such that an object of type InputIterator can be dereferenced and then implicitly converted to both of them. ​

[edit] Return value

Iterator past the end of the constructed range.

[edit] Complexity

At most 2·(N1+N2-1) comparisons, where N1 = std::distance(first1, last1) and N2 = std::distance(first2, last2).

[edit] Possible implementation

[edit] Example

[edit] See also

returns true if one set is a subset of another
(function template) [edit]
computes the difference between two sets
(function template) [edit]
computes the intersection of two sets
(function template) [edit]
computes the symmetric difference between two sets
(function template) [edit]