C++ Map Library - operator= Function

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Description

The C++ function std::multimap::operator= assign new contents to the multimap by replacing old ones and modifies size if necessary.

Declaration

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

C++98

multimap& operator= (const multimap& x);

C++11

multimap& operator= (const multimap& x);

Parameters

x − Another multimap object of same type.

Return value

Returns this pointer

Exceptions

No effect on container if exception is thrown.

Time complexity

Linear i.e. O(n)

Example

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

#include <iostream>
#include <map>

using namespace std;

int main(void) {
   /* Multimap with duplicates */
   multimap<char, int> m1 {
            {'a', 1},
            {'a', 2},
            {'b', 3},
            {'c', 4},
            {'d', 5}
         };

   multimap<char, int> m2;

   m2 = m1;

   cout << "Multimap 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 −

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