std::unordered_set<Key,Hash,KeyEqual,Allocator>::insert_range

From cppreference.com

 
C++
 
Containers library
 
std::unordered_set
Member types
Member functions
Iterators
Capacity
Modifiers
unordered_set::insert_range
(C++23)
(C++17)
(C++17)
Lookup
(C++20)
Bucket interface
Hash policy
Observers
Non-member functions
(until C++20)
(C++20)
Deduction guides(C++17)
 
template< container-compatible-range<value_type> R >
void insert_range( R&& rg );
 (since C++23)

Inserts a copy of each element of rg if and only if there is no element with key equivalent to the key of that element in *this.

Each iterator in the range rg is dereferenced exactly once. The behavior is undefined if rg overlaps with the container.


Parameters

rg - a container compatible range, that is, an input_range whose elements are convertible to T.
Type requirements
-
value_type must be EmplaceConstructible into unordered_set from *ranges::begin(rg). Otherwise, the behavior is undefined.

Return value

(none)

Complexity

Average case O(N), where N is ranges::distance(rg), worst case O(N·(a.size() + 1))

Notes

Feature-test macro Value Std Comment
__cpp_lib_containers_ranges 202202L (C++23) Ranges-aware construction and insertion

Example

Run this code
#include <iostream>
#include <unordered_set>
 
void println(auto, auto const& container)
{
    for (const auto& elem : container)
        std::cout << elem << ' ';
    std::cout << '\n';
}
 
int main()
{
    auto container = std::unordered_set{1, 3, 2, 4};
    const auto rg = {-1, 3, -2};
 
#ifdef __cpp_lib_containers_ranges
    container.insert_range(rg);
#else
    container.insert(rg.begin(), rg.end());
#endif
 
    println("{}", container);
}

Possible output: 

4 -1 2 3 -2 1

See also

(C++11)
 inserts elements or nodes (since C++17)
(public member function)
Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/container/unordered_set/insert_range&oldid=156368"