What is a C++ priority queue?

A C++ priority queue is a type of container adapter, specifically designed such that the first element of the queue is either the greatest or the smallest of all elements in the queue, and elements are in non-increasing or non-decreasing order (hence we can see that each element of the queue has a priority {fixed order}).

How do I add an element to a priority queue?

Adds an element to the priority queue based on the priority of the element from operator<. The element added to the top of the priority_queue. The top of the priority_queue is the position occupied by the largest element in the container. using namespace std; priority_queue q1; q1.push( 10 ); q1.push( 30 ); q1.push( 20 );

Why does a priority queue output first?

But because the priority queue outputs largest elements first, the elements that "come before" are actually output last. That is, the front of the queue contains the "last" element according to the weak ordering imposed by Compare. The following behavior-changing defect reports were applied retroactively to previously published C++ standards.