How to Declare a Map in C++?

In C++, maps are associative containers that store elements in a mapped fashion. Each element has a key value and a mapped value. No two mapped values can have the same key values. In this article, we will learn how to declare a map in C++.

In C++, you can declare a map using the std::map template class, which is part of the <map> header.

Syntax to declare a map in C++ STL

std::map<KeyType, ValueType> mapName;

where,

KeyType: This is the data type of the keys in the map.
ValueType: This is the data type of the values associated with the keys in the map.
mapName: This is the name you give to your map variable.

C++ Program to Declare a Map

C++

// C++ Program to declare a map 
#include <iostream> 
#include <map> 
#include <string> 
using namespace std; 
  
// Driver Code 
int main() 
{ 
    // Create a map of strings to integers 
    map<string, int> mp; 
  
    // Insert some values into the map 
    mp["one"] = 1; 
    mp["two"] = 2; 
    mp["three"] = 3; 
  
    // Get an iterator pointing to the first element in the 
    // map 
    map<string, int>::iterator it = mp.begin(); 
  
    // Iterate through the map and print the elements 
    while (it != mp.end()) { 
        cout << "Key: " << it->first 
             << ", Value: " << it->second << endl; 
        ++it; 
    } 
  
    return 0; 
}

Output

Key: one, Value: 1
Key: three, Value: 3
Key: two, Value: 2

Reffered: https://www.geeksforgeeks.org

C++

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