How to Declare a Map in C++?

How to Declare a Map in C++?

Last Updated : 28 Feb, 2024

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++.

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

How to Declare a Map in C++?

21mcsrltd

Improve

Article Tags :

Practice Tags :

CPP

Similar Reads

How to Declare a Vector in C++?

In C++, the vector is a dynamic array that can resize itself automatically to accommodate new elements. In this article, we will learn how to declare a vector in C++. Declare a Vector in C++In C++, vectors are defined as the class templates in <vector> header file. So, to declare a std::vector

How to Add Elements to a Map in C++?

In C++, a map is an associative container that stores the elements as key-value pairs where each element has a key and a mapped value. In this article, we will learn how to add elements to a map in C++ STL. For Example, Input: myMap = {{1, "Ram"}, {2, "Mohit"}}; Output: myMap = {{1, "Ram"}, {2, "Moh

How to Create a Stack of Map in C++?

In C++, the std::stack is a container that follows the LIFO (Last In, First Out) rule, whereas std::map is an associative container that stores key-value pairs. In this article, we will learn how to create a stack of a map in C++. Example:Input: myMap = { {1: â€˜aâ€™}, {2: â€˜bâ€™}, {3: â€˜câ€™} }; myMap = { {4

How to Create a Map of Arrays in C++?

In C++, the std::map is a container that stores elements in a key-value pair, whereas std::array is a sequence container that stores elements in contiguous memory. In this article, we will learn how to create a map of arrays in C++. Example: Input: arr1 = {1, 2, 3};arr2 = {4, 5, 6};arr3 = {7, 8, 9};

How to Create a Deque of Maps in C++?

In C++, the Standard Template Library (STL) provides a container called deque that allows efficient insertion and deletion operations at both ends of the container. A map is an associative container that stores elements in key-value pairs.In this article, we will learn how to create a deque of maps