C++ Map Library - insert() Function

Description

The C++ function std::map::insert() extends map by inserting new element from initializer list. This function increases container size by one.

Declaration

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

C++11

void insert (initializer_list<value_type> il);

Parameters

il − Initializer list.

Return value

None.

Exceptions

This member function doesn't throw exception.

Time complexity

Logarithmic i.e. O(log n).

Example

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

#include <iostream>
#include <map>

using namespace std;

int main(void) {
   map<char, int> m = {
            {'b', 2},
            {'c', 3},
            {'d', 4},
            };

   m.insert({{'e', 5}, {'a', 1}});

   cout << "Map contains following elements" << endl;

   for (auto it = m.begin(); it != m.end(); ++it)
      cout << it->first << " = " << it->second << endl;

   return 0;
}

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

Map contains following elements
a = 1
b = 2
c = 3
d = 4
e = 5