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| Sequence | ||||
(C++11) | ||||
(C++26) | ||||
(C++26) | ||||
(C++11) | ||||
| Associative | ||||
| Unordered associative | ||||
(C++11) | ||||
(C++11) | ||||
(C++11) | ||||
(C++11) | ||||
| Adaptors | ||||
(C++23) | ||||
(C++23) | ||||
(C++23) | ||||
(C++23) | ||||
| Views | ||||
(C++20) | ||||
(C++23) | ||||
| Tables | ||||
| Iterator invalidation | ||||
| Member function table | ||||
| Non-member function table |
std::unordered_set| Member types | ||||||
| Member functions | ||||||
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| Deduction guides(C++17) | ||||||
template<class H2,class P2> void merge(std::unordered_set<Key, H2, P2, Allocator>& source); | (1) | (since C++17) (constexpr since C++26) |
template<class H2,class P2> void merge(std::unordered_set<Key, H2, P2, Allocator>&& source); | (2) | (since C++17) (constexpr since C++26) |
template<class H2,class P2> void merge(std::unordered_multiset<Key, H2, P2, Allocator>& source); | (3) | (since C++17) (constexpr since C++26) |
template<class H2,class P2> void merge(std::unordered_multiset<Key, H2, P2, Allocator>&& source); | (4) | (since C++17) (constexpr since C++26) |
Attempts to extract (“splice”) each element insource and insert it into*this using the hash function and key equality predicate of*this.If there is an element in*this with key equivalent to the key of an element fromsource, then that element is not extracted fromsource.Ifget_allocator()== source.get_allocator() isfalse, the behavior is undefined.
No elements are copied or moved, only the internal pointers of the container nodes are repointed. All pointers and references to the transferred elements remain valid, but now refer into*this, not intosource.Iterators referring to the transferred elements and all iterators referring to*this are invalidated.Iterators to elements remaining insource remain valid.
Contents |
| source | - | compatible container to transfer the nodes from |
Given\(\scriptsize S\)S assize() and\(\scriptsize N\)N assource.size():
#include <iostream>#include <unordered_set> // print out a containertemplate<class Os,class K>Os& operator<<(Os& os,conststd::unordered_set<K>& v){ os<<'['<< v.size()<<"] {";bool o{};for(constauto& e: v) os<<(o?", ":(o=1," "))<< e;return os<<" }\n";} int main(){std::unordered_set<char> p{'C','B','B','A'}, q{'E','D','E','C'}; std::cout<<"p: "<< p<<"q: "<< q; p.merge(q); std::cout<<"p.merge(q);\n"<<"p: "<< p<<"q: "<< q;}
Possible output:
p: [3] { A, B, C }q: [3] { C, D, E }p.merge(q);p: [5] { E, D, A, B, C }q: [1] { C }(C++17) | extracts nodes from the container (public member function)[edit] |
| inserts elementsor nodes(since C++17) (public member function)[edit] |
