# std::unordered_multiset<Key,Hash,KeyEqual,Allocator>::insert_range

From cppreference.com
< cpp‎ | container‎ | unordered multiset

template< container-compatible-range<value_type> R > void insert_range( R&& rg ); |  | (since C++23)

Inserts a copy of each element of rg.

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_multiset` 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_multiset{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:

    1 -2 3 3 2 -1 4

### See also

insert (C++11) | inserts elements or nodes (since C++17) (public member function)

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