C++ Map Library - insert() Function


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Description

The C++ function std::multimap::insert() extends container by inserting new element in multimap. This function increases container size by one.

Declaration

Following is the declaration for std::multimap::insert() function form std::map header.

C++98

iterator insert (iterator position, const value_type& val);

C++11

iterator insert (const_iterator position, const value_type& val);

Parameters

  • position − Hint for the position to insert element.

  • val − value to be inserted.

Return value

Returns an iterator pointing to the newly inserted element.

Exceptions

No effect on container if exception is thrown.

Time complexity

Logarithmic i.e. O(log n)

Example

The following example shows the usage of std::multimap::insert() function.

#include <iostream>
#include <map>

using namespace std;

int main(void) {
   /* Multimap with duplicates */
   multimap<char, int> m {
            {'a', 1},
            {'a', 2},
            {'b', 3},
            {'c', 4},
         };

   auto pos = m.insert(m.begin(), pair<char, int>('a', 0));

   cout << "After inserting new element iterator points to" << endl;
   cout << pos->first << " = " << pos->second << endl;

   return 0;
}

Let us compile and run the above program, this will produce the following result −

After inserting new element iterator points to
a = 0
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