What are some examples of using std::queue in C++?

Can you give me some examples of using std::queue in C++?

Sure! The std::queue is a container adapter that provides a FIFO (first-in, first-out) data structure. Here's a simple example:

#include <iostream>
#include <queue>

int main() {
    std::queue<int> q;
    q.push(1);
    q.push(2);
    q.push(3);

    while (!q.empty()) {
        std::cout << q.front() << ' '; // Access the front element
        q.pop(); // Remove the front element
    }
    return 0;
}

This code will output: 1 2 3.

What happens if I try to access the front of an empty queue?

If you try to access the front of an empty queue using q.front(), it will lead to undefined behavior. It's important to check if the queue is empty using q.empty() before accessing the front element.

Can std::queue hold different data types?

No, std::queue can only hold elements of a single data type. If you need to store different types, you might consider using std::variant or a base class pointer.

How do I clear a queue in C++?

You can clear a queue by using a loop to pop all elements until it's empty, or you can create a new queue instance to replace it.