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Showing content from https://cplusplus.com/make_heap below:

function template

<algorithm>

template <class RandomAccessIterator>  void make_heap (RandomAccessIterator first, RandomAccessIterator last);

template <class RandomAccessIterator, class Compare>  void make_heap (RandomAccessIterator first, RandomAccessIterator last,                  Compare comp );

Make heap from range

A heap is a way to organize the elements of a range that allows for fast retrieval of the element with the highest value at any moment (with pop_heap), even repeatedly, while allowing for fast insertion of new elements (with push_heap).

The element with the highest value is always pointed by first. The order of the other elements depends on the particular implementation, but it is consistent throughout all heap-related functions of this header.

The elements are compared using operator< (for the first version), or comp (for the second): The element with the highest value is an element for which this would return false when compared to every other element in the range.

The standard container adaptor priority_queue calls make_heap, push_heap and pop_heap automatically to maintain heap properties for a container.

first, last

Random-access iterators to the initial and final positions of the sequence to be transformed into a heap. The range used is [first,last), which contains all the elements between first and last, including the element pointed by first but not the element pointed by last.
RandomAccessIterator shall point to a type for which swap is properly defined and which is both move-constructible and move-assignable.

comp

Binary function that accepts two elements in the range as arguments, and returns a value convertible to bool. The value returned indicates whether the element passed as first argument is considered to be less than the second in the specific strict weak ordering it defines.
The function shall not modify any of its arguments.
This can either be a function pointer or a function object.

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// range heap example
#include <iostream>     // std::cout
#include <algorithm>    // std::make_heap, std::pop_heap, std::push_heap, std::sort_heap
#include <vector>       // std::vector

int main () {
  int myints[] = {10,20,30,5,15};
  std::vector<int> v(myints,myints+5);

  std::make_heap (v.begin(),v.end());
  std::cout << "initial max heap   : " << v.front() << '\n';

  std::pop_heap (v.begin(),v.end()); v.pop_back();
  std::cout << "max heap after pop : " << v.front() << '\n';

  v.push_back(99); std::push_heap (v.begin(),v.end());
  std::cout << "max heap after push: " << v.front() << '\n';

  std::sort_heap (v.begin(),v.end());

  std::cout << "final sorted range :";
  for (unsigned i=0; i<v.size(); i++)
    std::cout << ' ' << v[i];

  std::cout << '\n';

  return 0;
}

initial max heap   : 30
max heap after pop : 20
max heap after push: 99
final sorted range : 5 10 15 20 99

push_heap

Push element into heap range (function template)

pop_heap

Pop element from heap range (function template)

sort_heap

Sort elements of heap (function template)

reverse

Reverse range (function template)

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