CPP STL Tutorial : C++ std::priority_queue and it’s operations.

In this chapter we shall learn about:

1. priority_queue introduction.

2. priority_queue operations.

3. priority_queue member declaration.

4. priority_queue member functions

1. priority_queue is a type of container adapter.

2. It supports FIFO [First In First Out].

3. FIFO means, that the elements are inserted first will be removed first.

Below is the header file to be used for stack:

#include <queue>          // std::stack

priority_queue will support below operations:

empty
size
front
back
push_back
pop_front

std::priority_queue<int> mypriority_queue;
mypriority_queue.push (1);
mypriority_queue.push (2);
mypriority_queue.push (3);
mypriority_queue.push (4);

empty : It will test whether container is empty

size : It will return size

push : It will insert element

pop : It will remove element

top   : It will access top element

#include <iostream>
#include <queue>
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using namespace std;

int main ()
{

  std::priority_queue<int> mypq;
  mypq.push (1);
  mypq.push (2);
  mypq.push (3);
  mypq.push (4);
  
  cout<<"Size of mypq is "<< mypq.size()<<endl;
  cout<<"mypq elements are: "<<endl;

   while (!mypq.empty())
  {
     std::cout << ' ' << mypq.top();
     mypq.pop();
  }
  return 0;
}

Size of mypq is 4
mypq elements are:
4 3 2 1