Implement Dictionary using Multimap in C++

Hello Folks!!!

Welcome to this tutorial in which you are going to learn how to implement a Dictionary using multimap in C++.

• Dictionary is a built-in data type in Python that stores data in the key-value pair. So here in this tutorial, we will write a C++ program that will work similarly to the Dictionary in Python.

Problem:

Implement a dictionary using multimap by storing a few words having multiple meanings. For eg., “Apple” is both a fruit and the name of a company, “Kiwi” is both a fruit and a bird.

Example:

Apple: A fruit
Apple: A company

Kiwi: A fruit
Kiwi: A bird.

Approach:

• Although, using Multimap is not the best way of implementing a dictionary as it can be more optimized by using the Trie data structure, but we have used this to explain one of the many uses of a multimap.
• To do this, just create a multimap and store in it a key and its multiple values. There is a single key that can have more than one value.
• The insert function can be used to insert multiple pairs of values into a multimap having the same key but different values.
• Then this multimap can be displayed using the begin and end operation implemented through a for loop.

Program:

// C++ code illustrating how to
// implement dictionary using a multimap

#include <bits/stdc++.h>
using namespace std;

// Main function
int main(void)
{
    // Declaring a multimap
    multimap<string, string> D;

    // Inserting key_value pair1
    D.insert( pair<string, string> ("Kiwi", "A fruit") );

    // Inserting key_value pair2
    D.insert( pair<string, string> ("Kiwi", "A Bird") );

    // Displaying the contents of multimap
    for (auto it = D.begin(); it != D.end(); it++) 
        cout << it->first << " : " << it->second << " " <<"\n";

return 0;
}

If you try to run the above program then you will get the output as,

Kiwi : A fruit

Kiwi : A Bird

So that’s all for this tutorial. I hope you have understood the concept thoroughly.

Thank you for going through this tutorial.

Comment down for any queries.