Vector Pair in C++

The C++ can use a vector of pairs to store and manipulate a collection of pairs of elements. A std::pair is a simple template class provided by the C++ Standard Library that allows you to store two values of potentially different types together. Here’s how you can create and use a vector of pairs in C++:

#include <iostream>
#include <vector>
#include <utility> // Include the utility header for std::pair

int main() {
    // Create a vector of pairs
    std::vector<std::pair<int, std::string>> vec;

    // Add elements to the vector of pairs
    vec.push_back(std::make_pair(1, "One"));
    vec.push_back(std::make_pair(2, "Two"));
    vec.push_back(std::make_pair(3, "Three"));

    // Access elements in the vector of pairs
    for (const auto& pair : vec) {
        std::cout << pair.first << ": " << pair.second << std::endl;
    }

    return 0;
}

In this example:

1. We include the <utility> header to use std::pair.
2. We create a vector vec that stores pairs where the first element is an integer (int) and the second element is a string (std::string).
3. We use std::make_pair to create pairs and push_back to add them to the vector.
4. We iterate through the vector using a range-based for loop to access and print the elements of each pair.

Output:

1: One
2: Two
3: Three

You can use vectors of pairs to store and manipulate collections of pairs, such as key-value pairs or any other combination of two values. They are especially useful when you need to maintain associations between two related pieces of data.