std::map::insert
From cppreference.com
std::pair<iterator,bool> insert( const value_type& value );
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(1) | |
template< class P >
std::pair<iterator,bool> insert( P&& value ); |
(2) | (since C++11) |
std::pair<iterator,bool> insert( value_type&& value );
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(2) | (since C++17) |
(3) | ||
iterator insert( iterator hint, const value_type& value );
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(until C++11) | |
iterator insert( const_iterator hint, const value_type& value );
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(since C++11) | |
template< class P >
iterator insert( const_iterator hint, P&& value ); |
(4) | (since C++11) |
iterator insert( const_iterator hint, value_type&& value );
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(4) | (since C++17) |
template< class InputIt >
void insert( InputIt first, InputIt last ); |
(5) | |
void insert( std::initializer_list<value_type> ilist );
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(6) | (since C++11) |
Inserts element(s) into the container, if the container doesn't already contain an element with an equivalent key.
1-2) Inserts
value
. The overload (2) is equivalent to emplace(std::forward<P>(value)) and only participates in overload resolution if std::is_constructible<value_type, P&&>::value == true.
3-4) Inserts
value
in the position as close as possible, just prior(since C++11), to hint
. The overload (4) is equivalent to emplace_hint(hint, std::forward<P>(value)) and only participates in overload resolution if std::is_constructible<value_type, P&&>::value == true.
5) Inserts elements from range
[first, last)
.
6) Inserts elements from initializer list
ilist
.No iterators or references are invalidated.
Contents |
[edit] Parameters
hint | - |
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||||
value | - | element value to insert | ||||
first, last | - | range of elements to insert | ||||
ilist | - | initializer list to insert the values from | ||||
Type requirements | ||||||
-
InputIt must meet the requirements of InputIterator .
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[edit] Return value
1-2) Returns a pair consisting of an iterator to the inserted element (or to the element that prevented the insertion) and a bool denoting whether the insertion took place.
3-4) Returns an iterator to the inserted element, or to the element that prevented the insertion.
5-6) (none)
[edit] Exceptions
1-4) If an exception is thrown by any operation, the insertion has no effect.
This section is incomplete Reason: cases 5-6 |
[edit] Complexity
1-2) Logarithmic in the size of the container,
O(log(size()))
.
3-4) Amortized constant if the insertion happens in the position just after the hint, logarithmic in the size of the container otherwise.
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(until C++11) |
3-4) Amortized constant if the insertion happens in the position just before the hint, logarithmic in the size of the container otherwise.
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(since C++11) |
5-6)
O(N*log(size() + N))
, where N is the number of elements to insert.[edit] Notes
The hinted insert (3,4) does not return a boolean in order to be signature-compatible with positional insert on sequential containers, such as std::vector::insert. This makes it possible to create generic inserters such as std::inserter. One way to check success of a hinted insert is to compare size() before and after.
[edit] See also
(C++11)
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constructs element in-place (public member function) |
(C++11)
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constructs elements in-place using a hint (public member function) |