Priority Queue:
This container comes under derived or adaptor container, this follow priority value (first element out will have highest priority). It has similar interface of queue.
Header File:
#include<queue>
Key Points:
- It is used to store the data, we can store any number of element and remove from it.
- Internally its implemented as vector we can change to other container.
- push(): insert the element.
- pop(): remove the element.
- top(): return the top element BUT will not remove the element.
- size(): return the size / number of element in it.
- empty(): return true if queue is empty otherwise false.
How to add element in priority queue:
Source code of std::priority queue with example:
/*
Program: STL Priority Queue
Author: Alpha Master
Date: 20 September 2021
*/
//Header File
#include<iostream>
#include<queue>
int main()
{
std::cout<<"STL Priority Queue"<<std::endl;
//Create empty priority queue object
std::priority_queue<int> pq;
std::cout<<"size:"<<pq.size()<<std::endl;
//Add element
pq.push(1);
pq.push(2);
pq.push(3);
pq.push(4);
pq.push(5);
std::cout<<"size:"<<pq.size()<<std::endl;
//Top element
std::cout<<"Execute Top command:";
std::cout<<pq.top()<<std::endl;
//Remove element
std::cout<<"Execute pop command"<<std::endl;
pq.pop();
//Top element
std::cout<<"Execute Top command:";
std::cout<<pq.top()<<std::endl;
std::cout<<"Display the complete"<<std::endl;
//Display the element
while(!pq.empty())
{
std::cout<<pq.top()<<" ";
pq.pop();
}
std::cout<<std::endl;
return 0;
}
Output:
STL Priority Queue size:0 size:5 Execute Top command:5 Execute pop command Execute Top command:4 Display the complete 4 3 2 1