What is the difference between std::queue and std::priority_queue in C++11?

What is the difference between std::queue and std::priority_queue in C++11?

In C++11, std::queue is a FIFO (First In, First Out) data structure, while std::priority_queue is a max-heap that allows access to the highest priority element.

Can you give me an example of how to use both?

Sure! For std::queue, you can use it like this:

#include <queue>
std::queue<int> q;
q.push(1);
q.push(2);
int front = q.front(); // front is 1
q.pop(); // removes 1

For std::priority_queue:

#include <queue>
std::priority_queue<int> pq;
pq.push(2);
pq.push(1);
int top = pq.top(); // top is 2
pq.pop(); // removes 2

What are the performance differences between them?

std::queue has O(1) time complexity for push and pop operations, while std::priority_queue has O(log n) for push and pop due to the heap structure.

When should I use one over the other?

Use std::queue when you need a simple FIFO structure. Use std::priority_queue when you need to process elements based on priority.