What is the difference between a queue and a priority queue in C++?

What is the difference between a queue and a priority queue in C++?

In C++, a queue is a data structure that follows the First In First Out (FIFO) principle, while a priority queue allows elements to be processed based on their priority.

Can you give me an example of how to implement both in C++?

Sure! For a queue, you can use the std::queue class, and for a priority queue, you can use std::priority_queue. Here's a simple example:

#include <queue>
#include <iostream>

int main() {
    std::queue<int> q;
    q.push(1);
    q.push(2);
    std::cout << "Queue front: " << q.front() << '\n';
    q.pop();

    std::priority_queue<int> pq;
    pq.push(2);
    pq.push(1);
    std::cout << "Priority Queue top: " << pq.top() << '\n';
    return 0;
}

What are the use cases for each type of queue?

Queues are often used in scenarios like task scheduling and buffering, while priority queues are useful in algorithms like Dijkstra's for shortest paths or in scheduling tasks with different priorities.

Are there any performance differences between them?

Yes, queues generally have O(1) time complexity for enqueue and dequeue operations, while priority queues have O(log n) for insertion and O(1) for accessing the highest priority element.