priority queue in c++

// C++ program to demonstrate min heap 
#include <iostream> 
#include <queue> 
  
using namespace std; 
  
void showpq(priority_queue <int, vector<int>, greater<int>> gq) 
{ 
    priority_queue <int, vector<int>, greater<int>> g = gq; 
    while (!g.empty()) 
    { 
        cout << '\t' << g.top(); 
        g.pop(); 
    } 
    cout << '\n'; 
} 
  
int main () 
{ 
   //for max heap // by default use 
  // priority_queue<type>name;
  // for min heap//
    priority_queue <int, vector<int>, greater<int>> gquiz; 
    gquiz.push(10); 
    gquiz.push(30); 
    gquiz.push(20); 
    gquiz.push(5); 
    gquiz.push(1); 
  
    cout << "The priority queue gquiz is : "; 
    showpq(gquiz); 
  
    cout << "\ngquiz.size() : " << gquiz.size(); 
    cout << "\ngquiz.top() : " << gquiz.top(); 
  
  
    cout << "\ngquiz.pop() : "; 
    gquiz.pop(); 
    showpq(gquiz); 
  
    return 0; 
}

// using GCC 10.2 (C++2a) compiler
#include <functional>
#include <queue>
#include <vector>
#include <iostream>
 
template<typename T> void print_queue(T& q) {
    while(!q.empty()) {
        std::cout << q.top() << " ";
        q.pop();
    }
    std::cout << '\n';
}
 
int main() {
    std::priority_queue<int> q;
 
    for(int n : {1,8,5,6,3,4,0,9,7,2})
        q.push(n);
 
    print_queue(q);
 
    std::priority_queue<int, std::vector<int>, std::greater<int> > q2;
 
    for(int n : {1,8,5,6,3,4,0,9,7,2})
        q2.push(n);
 
    print_queue(q2);
 
    // Using lambda to compare elements.
    auto cmp = [](int left, int right) { return (left ^ 1) < (right ^ 1); };
    std::priority_queue<int, std::vector<int>, decltype(cmp)> q3(cmp);
 
    for(int n : {1,8,5,6,3,4,0,9,7,2})
        q3.push(n);
 
    print_queue(q3);
 
}

//Shubh'grepper
// Implementation of priority_queue in c++

//queue with elements in decreasing order
priority_queue<int> pq;

// queue with elements in increasing order  using compare function inside declaration
priority_queue <int, vector<int>, greater<int> > pq;

//priority_queue of type pair<int, int>
#define pp pair<int, int>
priority_queue <pp, vector<pp>, greater<pp> > pq;

// Note that by default C++ creates a max-heap 
// for priority queue 
#include <iostream> 
#include <queue> 
  
using namespace std; 
  
void showpq(priority_queue <int> gq) 
{ 
    priority_queue <int> g = gq; 
    while (!g.empty()) 
    { 
        cout << '\t' << g.top(); 
        g.pop(); 
    } 
    cout << '\n'; 
} 
  
int main () 
{ 
    priority_queue <int> gquiz; 
    gquiz.push(10); 
    gquiz.push(30); 
    gquiz.push(20); 
    gquiz.push(5); 
    gquiz.push(1); 
  
    cout << "The priority queue gquiz is : "; 
    showpq(gquiz); 
  
    cout << "\ngquiz.size() : " << gquiz.size(); 
    cout << "\ngquiz.top() : " << gquiz.top(); 
  
  
    cout << "\ngquiz.pop() : "; 
    gquiz.pop(); 
    showpq(gquiz); 
  
    return 0; 
}