std::multimap insert() method

since C++17

// (1) Non const version only
iterator insert( value_type&& value );

// (2) Non const version only
template< class P >
iterator insert( P&& value );

// (3) Non const version only
iterator insert( const_iterator hint, value_type&& value );

// (4) Non const version only
template< class P >
iterator insert( const_iterator hint, P&& value );

// (5) Non const  version only
template< class InputIt >
void insert( InputIt first, InputIt last );

// (6) Non const  version only
void insert( std::initializer_list<value_type> ilist );

// (7) Non const  version only
iterator insert( node_type&& nh );

// (8) Non const  version only
iterator insert( const_iterator hint, node_type&& nh );

since C++11

// (1) Non const version only
iterator insert( const value_type& value );

// (2) Non const version only
template< class P >
iterator insert( P&& value );

// (3) Non const version only
iterator insert( const_iterator hint, const value_type& value );

// (4) Non const version only
template< class P >
iterator insert( const_iterator hint, P&& value );

// (5) Non const  version only
template< class InputIt >
void insert( InputIt first, InputIt last );

// (6) Non const  version only
void insert( std::initializer_list<value_type> ilist );

until C++11

// (1) Non const version only
iterator insert( const value_type& value );

// (3) Non const version only
iterator insert( iterator hint, const value_type& value );

// (5) Non const  version only
template< class InputIt >
void insert( InputIt first, InputIt last );

Inserts element(s) into the container, if the container doesn't already contain an element with an equivalent key.

• (1-2) Inserts value.

  since C++11

  If the container has elements with equivalent key, inserts at the upper bound of that range. 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.

  until C++11

  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, 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 ).

• (8) Inserts elements from initializer list ilist.

• (9) If nh is an empty node handle, does nothing. Otherwise, inserts the element owned by nh into the container, if the container doesn't already contain an element with a key equivalent to nh.key(). The behavior is undefined if nh is not empty and get_allocator() != nh.get_allocator().

• (10) If nh is an empty node handle, does nothing and returns the end iterator. Otherwise, inserts the element owned by nh into the container, if the container doesn't already contain an element with a key equivalent to n.key(), and returns the iterator pointing to the element with key equivalent to nh.key() (regardless of whether the insert succeeded or failed). If the insertion succeeds, nh is moved from, otherwise it retains ownership of the element. The element is inserted as close as possible to the position just prior to hint. The behavior is undefined if nh is not empty and get_allocator() != nh.get_allocator().

since C++17

No iterators or references are invalidated.

until C++11

Invalidation

If the insertion is successful, pointers and references to the element obtained while it is held in the node handle are invalidated, and pointers and references obtained to that element before it was extracted become valid.

Parameters

• hint
  since C++11

  iterator to the position before which the new element will be inserted

  until C++11

  iterator, used as a suggestion as to where to start the search
• value - element value to insert
• first, last - the range of elements to insert
• ilist - initializer list to insert the values from
• nh - a compatible node handle

Type requirements

• (5) - InputIt must meet the requirements of LegacyInputIterator.

Return value

• (1-4) Returns an iterator to the inserted element.
• (5-6) (none)
• (7-8) End iterator if nh is empty, iterator pointing to the inserted element otherwise.

Complexity

• (1-2) Logarithmic in the size of the container - O(log size()).
• (4-6)
  since C++11

  Amortized constant if the insertion happens in the position just before the hint - O(1).
  Logarithmic in the size of the container otherwise - O(log size()).

  until C++11

  Amortized constant if the insertion happens in the position just after the hint - O(1).
  Logarithmic in the size of the container otherwise - O(log size()).
• (7-8) O(N * log(size() + N)), where N is the number of elements to insert.
• (9) Logarithmic in the size of the container - O(log size()).
• (10)
  Amortized constant if the insertion happens in the position just before the hint - O(1).
  Logarithmic in the size of the container otherwise - O(log size()).

Exceptions

• (1-4) If an exception is thrown by any operation, the insertion has no effect.

important

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Example

Main.cpp

#include <iostream>
#include <string>
#include <map>
#include <utility>
#include <functional>
#include <string_view>
 
template<class M>
void print(const std::string_view rem, const M& mmap)
{
    std::cout << rem << " ";
    for (const auto & e : mmap)
        std::cout << "{" << e.first << "," << e.second << "} ";
    std::cout << '\n';
}
 
int main()
{
    // list-initialize
    std::multimap<int, std::string, std::greater<int>> mmap
        {{2, "foo"}, {2, "bar"}, {3, "baz"}, {1, "abc"}, {5, "def"}};
    print("#1", mmap);
 
    // insert using value_type
    mmap.insert(decltype(mmap)::value_type(5, "pqr"));
    print("#2", mmap);
 
    // insert using pair
    mmap.insert(std::pair{6, "uvw"});
    print("#3", mmap);
 
    mmap.insert({7, "xyz"});
    print("#4", mmap);
 
    // insert using initializer_list
    mmap.insert({{5, "one"}, {5, "two"}});
    print("#5", mmap);
 
    // insert using a pair of iterators
    mmap.clear();
    const auto il = { std::pair{1, "ä"}, {2, "ё"}, {2, "ö"}, {3, "ü"} };
    mmap.insert(il.begin(), il.end());
    print("#6", mmap);
}

Output

#1 {5,def} {3,baz} {2,foo} {2,bar} {1,abc}
#2 {5,def} {5,pqr} {3,baz} {2,foo} {2,bar} {1,abc}
#3 {6,uvw} {5,def} {5,pqr} {3,baz} {2,foo} {2,bar} {1,abc}
#4 {7,xyz} {6,uvw} {5,def} {5,pqr} {3,baz} {2,foo} {2,bar} {1,abc}
#5 {7,xyz} {6,uvw} {5,def} {5,pqr} {5,one} {5,two} {3,baz} {2,foo} {2,bar} {1,abc}
#6 {3,ü} {2,ё} {2,ö} {1,ä}