C++ Map Library - operator= Function

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Description

The C++ function std::map::operator= copy elements from initializer list to map.

Declaration

Following is the declaration for std::map::operator= function form std::map header.

C++11

map& operator= (initializer_list<value_type> il);

Parameters

il − Initialize list.

Return value

Returns this pointer

Exceptions

This member function never throws exception.

Time complexity

Linear i.e. O(n)

Example

The following example shows the usage of std::map::operator= function.

#include <iostream>
#include <map>

using namespace std;

int main(void) {
   map<char, int> m;

   m =  {
      {'a', 1},
      {'b', 2},
      {'c', 3},
      {'d', 4},
      {'e', 5},
        };

   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