| CARVIEW |
Select Language
HTTP/1.1 301 Moved Permanently
Server: nginx
Date: Sat, 19 Jul 2025 10:41:35 GMT
Content-Type: text/html; charset=UTF-8
Transfer-Encoding: chunked
Connection: keep-alive
Location: /reference/map/multimap/operator=/
HTTP/1.1 200 OK
Server: nginx
Date: Sat, 19 Jul 2025 10:41:36 GMT
Content-Type: text/html; charset=utf-8
Transfer-Encoding: chunked
Connection: keep-alive
ETag: W/"855d-7/41h1YKO/AbMRFtMgj+SQdbhV0"
Content-Encoding: gzip
Assigns new contents to the container, replacing its current content.
The elements stored in the container before the call are either assigned to or destroyed.
Output:
For the move assignment (2): Linear in current container size (destructions).*
For the initializer list assignment (3): Up to logarithmic in sizes (destructions, move-assignments) -- linear if il is already sorted.
* Additional complexity for assignments if allocators do not propagate.
In the move assignment, iterators, pointers and references referring to elements in x are also invalidated.
The move assignment (2) modifies x.
The container and all its elements are modified.
If allocator_traits::construct is not supported with the appropriate arguments for the element constructions, or if value_type is not copy assignable (or move assignable for (2)), it causes undefined behavior.
Reference
C library:
- <cassert> (assert.h)
- <cctype> (ctype.h)
- <cerrno> (errno.h)
-
<cfenv> (fenv.h)C++11
- <cfloat> (float.h)
-
<cinttypes> (inttypes.h)C++11
- <ciso646> (iso646.h)
- <climits> (limits.h)
- <clocale> (locale.h)
- <cmath> (math.h)
- <csetjmp> (setjmp.h)
- <csignal> (signal.h)
- <cstdarg> (stdarg.h)
-
<cstdbool> (stdbool.h)C++11
- <cstddef> (stddef.h)
-
<cstdint> (stdint.h)C++11
- <cstdio> (stdio.h)
- <cstdlib> (stdlib.h)
- <cstring> (string.h)
-
<ctgmath> (tgmath.h)C++11
- <ctime> (time.h)
-
<cuchar> (uchar.h)C++11
- <cwchar> (wchar.h)
- <cwctype> (wctype.h)
Containers:
-
<array>C++11
- <deque>
-
<forward_list>C++11
- <list>
- <map>
- <queue>
- <set>
- <stack>
-
<unordered_map>C++11
-
<unordered_set>C++11
- <vector>
-
Input/Output:
Multi-threading:
-
<atomic>C++11
-
<condition_variable>C++11
-
<future>C++11
-
<mutex>C++11
-
<thread>C++11
-
Other:
- <algorithm>
- <bitset>
-
<chrono>C++11
-
<codecvt>C++11
- <complex>
- <exception>
- <functional>
-
<initializer_list>C++11
- <iterator>
- <limits>
- <locale>
- <memory>
- <new>
- <numeric>
-
<random>C++11
-
<ratio>C++11
-
<regex>C++11
- <stdexcept>
- <string>
-
<system_error>C++11
-
<tuple>C++11
-
<type_traits>C++11
-
<typeindex>C++11
- <typeinfo>
- <utility>
- <valarray>
multimap
- multimap::~multimap
- multimap::multimap
member functions
- multimap::begin
-
multimap::cbeginC++11
-
multimap::cendC++11
- multimap::clear
- multimap::count
-
multimap::crbeginC++11
-
multimap::crendC++11
-
multimap::emplaceC++11
-
multimap::emplace_hintC++11
- multimap::empty
- multimap::end
- multimap::equal_range
- multimap::erase
- multimap::find
- multimap::get_allocator
- multimap::insert
- multimap::key_comp
- multimap::lower_bound
- multimap::max_size
- multimap::operator=
- multimap::rbegin
- multimap::rend
- multimap::size
- multimap::swap
- multimap::upper_bound
- multimap::value_comp
non-member overloads
public member function
<map>
std::multimap::operator=
| copy (1) | multimap& operator= (const multimap& x); |
|---|
| copy (1) | multimap& operator= (const multimap& x); |
|---|---|
| move (2) | multimap& operator= (multimap&& x); |
| initializer list (3) | multimap& operator= (initializer_list<value_type> il); |
Copy container content
Copies all the elements from x into the container, changing its size accordingly.
The container preserves its current allocator, which is used to allocate additional storage if needed.
The container preserves its current allocator, which is used to allocate additional storage if needed.
The copy assignment (1) copies all the elements from x into the container (with x preserving its contents).
The move assignment (2) moves the elements of x into the container (x is left in an unspecified but valid state).
The initializer list assignment (3) copies the elements of il into the container.
The new container size is the same as the size of x (or il) before the call.
The container preserves its current allocator, except if the allocator traits indicate x's allocator should propagate. This allocator is used (through its traits) to allocate or deallocate if there are changes in storage requirements, and to construct or destroy elements, if needed.
The move assignment (2) moves the elements of x into the container (x is left in an unspecified but valid state).
The initializer list assignment (3) copies the elements of il into the container.
The new container size is the same as the size of x (or il) before the call.
The container preserves its current allocator, except if the allocator traits indicate x's allocator should propagate. This allocator is used (through its traits) to allocate or deallocate if there are changes in storage requirements, and to construct or destroy elements, if needed.
The elements stored in the container before the call are either assigned to or destroyed.
Parameters
- x
- A multimap object of the same type (i.e., with the same template parameters, key, T, Compare and Alloc).
- il
- An initializer_list object. The compiler will automatically construct such objects from initializer list declarators.
Member type value_type is the type of the elements in the container, defined in multimap as an alias of pair<const key_type, mapped_type> (see multimap member types).
Return value
*thisExample
|
|
Size of foo: 0 Size of bar: 4 |
Complexity
For the copy assignment (1): Linear in sizes (destructions, copies).For the move assignment (2): Linear in current container size (destructions).*
For the initializer list assignment (3): Up to logarithmic in sizes (destructions, move-assignments) -- linear if il is already sorted.
* Additional complexity for assignments if allocators do not propagate.
Iterator validity
All iterators, references and pointers related to this container are invalidated.In the move assignment, iterators, pointers and references referring to elements in x are also invalidated.
Data races
All copied elements are accessed.The move assignment (2) modifies x.
The container and all its elements are modified.
Exception safety
Basic guarantee: if an exception is thrown, the container is in a valid state.If allocator_traits::construct is not supported with the appropriate arguments for the element constructions, or if value_type is not copy assignable (or move assignable for (2)), it causes undefined behavior.
See also
- multimap::insert
- Insert element (public member function)
- multimap::find
- Get iterator to element (public member function)
- multimap::multimap
- Construct multimap (public member function)
Home page | Privacy policy
© cplusplus.com, 2000-2025 - All rights reserved - v3.3.4s
Spotted an error? contact us
© cplusplus.com, 2000-2025 - All rights reserved - v3.3.4s
Spotted an error? contact us