C++ Map Library - insert() Function


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Description

The C++ function std::map::insert() extends container by inserting new elements in the map.

Declaration

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

C++98

template <class InputIterator>
void insert (InputIterator first, InputIterator last);

C++11

template <class InputIterator>
void insert (InputIterator first, InputIterator last);

Parameters

  • first − Input iterator to the initial position in range.

  • last − Input iterator to the final position in range.

Return value

None

Exceptions

This member function doens'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) {
   /* Initializer_list constructor */
   map<char, int> m1 = {
            {'a', 1},
            {'b', 2},
            {'c', 3},
            {'d', 4},
            {'e', 5},
            };

   map<char, int> m2;

   m2.insert(m1.begin(), m1.end());

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

   for (auto it = m2.begin(); it != m2.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
map.htm
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