C++11: Standard Priority Queue vs. Queue

What are the main differences between std::priority_queue and std::queue in C++11?

The main difference is that std::priority_queue is a container adaptor that provides a way to access the largest element first, while std::queue is a simple FIFO (first-in, first-out) structure.

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

Sure! Here's a simple example:

#include <queue>
#include <vector>
#include <iostream>

int main() {
    std::priority_queue<int> pq;
    pq.push(10);
    pq.push(20);
    pq.push(15);

    while (!pq.empty()) {
        std::cout << pq.top() << ' '; // Outputs: 20 15 10
        pq.pop();
    }
    return 0;
}

When should I use std::priority_queue instead of std::queue?

Use std::priority_queue when you need to process elements based on priority rather than the order they were added. For example, in scheduling tasks where some tasks are more important than others.

Are there any performance differences between the two?

Yes, std::priority_queue has a logarithmic time complexity for insertion and removal of elements, while std::queue has constant time complexity for insertion and removal. This means std::priority_queue can be slower for large datasets.