What is the usage of std::unordered_set in C++17?

What is the usage of std::unordered_set in C++17?

In C++17, std::unordered_set is a container that stores unique elements in no particular order, allowing for fast retrieval.

Can you give me an example of how to use std::unordered_set?

Sure! Here's a simple example:

#include <iostream>
#include <unordered_set>

int main() {
    std::unordered_set<int> mySet;
    mySet.insert(1);
    mySet.insert(2);
    mySet.insert(3);

    for (const auto& elem : mySet) {
        std::cout << elem << " ";
    }
    return 0;
}

This code creates an unordered set of integers and inserts three elements.

What are the advantages of using std::unordered_set over std::set?

The main advantage of std::unordered_set is its average constant time complexity for insertions and lookups, compared to std::set, which has logarithmic time complexity due to its ordered nature.

Are there any limitations to using std::unordered_set?

Yes, std::unordered_set does not maintain the order of elements, and it requires a hash function for the type of elements stored. Additionally, it may use more memory than std::set.