Concept of heapify in C++

heap.hpp

#ifndef ALGORITHM_HEAP_H_
#define ALGORITHM_HEAP_H_ 1

#include <functional>
#include <utility>
#include <vector>
#include <iostream>

namespace algorithm
{

template<
    typename ElementType,
    typename ElementCompareFunc = std::less<ElementType>,
    typename HeapType           = std::vector<ElementType>
>
class Heap : public HeapType
{
private:
    typedef int KeyType;

    inline
    KeyType
    parent(const KeyType & me)
    const
    { return ((me - 1) / 2); }

    inline
    KeyType
    left(const KeyType & me)
    const
    { return (2 * me + 1); }

    inline
    KeyType
    right(const KeyType & me)
    const
    { return (2 * me + 2); }

public:
    void
    Heapify(void)
    {
        for(int pos = this->size() - 1; pos >= 0; --pos)
        {
            KeyType start = this->parent(pos);
            KeyType end = pos;

            if(ElementCompareFunc()(this->at(start), this->at(pos)))
                continue;

            printf("START: %d (POS: %d)\n", start, pos);
            printf("    LEFT: %d\n"
                    "   RIGHT: %d\n", left(pos), right(pos));

            //while(left(last) < this->size() && ElementCompareFunc()(this->at(last = (ElementCompareFunc()(this->at(left(last)), this->at(right(last))) ? left(last) : right(last))), this->at(pos)))
            while(right(end) < this->size())
            {
                KeyType temp = (ElementCompareFunc()(this->at(left(end)), this->at(right(end))) ? left(end) : right(end));
                if(ElementCompareFunc()(this->at(temp), this->at(pos)))
                    break;

                end = temp;
                printf("END: %d\n", end);
            }

            printf("END: %d (POS: %d)\n", end, pos);

            if(end == pos)
                std::swap(this->at(start), this->at(pos));
            else
            {
                KeyType cpos = end; /** Child position */
                do
                {
                    cpos = parent(pos);
                    std::swap(this->at(end), this->at(cpos));
                }
                while(cpos != parent(pos));
            }

            for(int i = 0; i < this->size(); ++i)
                printf("%3d ", this->at(i));
            std::cout << std::endl;
        }
    }
};

}

using namespace algorithm;

int main(void)
{
    int arr[] = { 7, 5, 13, 0, 1, 7, 6, 4, 3, 2 };

    Heap<int> heap;
    heap.insert(heap.begin(), arr, arr + 10);

    heap.Heapify();

    for(auto node : heap)
        printf("%3d ", node);
    std::cout << std::endl;

    return 0;
};

#endif