How to Create a Vector of Pairs in C++?

In C++, vectors are dynamic arrays that can store a collection of data. Pairs are data structure­ to store two different types of objects in the form of key and value. In this article, we will see how to create a vector of pairs in C++.

Vector of Pairs in C++

In C++, you can create a vector of pairs by declaring a std::vector with a std::pair type. It will create a vector container where each element will be a pair consisting of a key and a value. The below syntax shows how to do it:

Syntax

vector<pair<int, char>> myVector;

C++ Program to Create the Vector of Pairs

C++

// C++ program to create the Vector of Pairs
#include <iostream>
#include <utility>
#include <vector>
using namespace std;

// Driver Code
int main()
{
    // Declare a vector of pairs, where each pair
    // contains an integer and a character
    vector<pair<int, char> > vecOfPairs;

    // creating pairs
    pair<int, char> p1, p2;
    p1 = make_pair(1, 'A');
    p2 = make_pair(2, 'B');

    // inserting pairs to the vector
    vecOfPairs.push_back(p1);
    vecOfPairs.push_back(p2);

    // Iterate over the vector of pairs
    // using a range-based for loop
    for (const auto& pair : vecOfPairs) {

        std::cout << "(" << pair.first << ", "
                  << pair.second << ")" << std::endl;
    }

    return 0;
}

Output

(1, A)
(2, B)

Time Complexity: O(N), where N is the number of pairs.
Auxiliary Space: O(N)