Improvements

Hello..
Below is my implementation of a max heap ..
I'd be grateful if any one can suggest any improvements .. or any better ways to implement

Thanks a lot !

Code:

#include <cstdio>
#include <cstring>
#include <vector>
#include <algorithm>
using namespace std;

template <class T>
class max_heap
{
	private:
	vector< T >heap;

	inline int LEFT(const int &i) { return (i<<1)+1; }
	inline int RIGHT(const int &i) { return (i<<1)+2; }
	inline int PARENT(const int &i) { return (i&1)?i>>1:(i>>1)-1; }

	void max_heapify(int i)
	{
		int left=LEFT(i);
		int right=RIGHT(i);
		int largest=i;

		if(left < heap.size() && heap[left] > heap[largest]) largest=left;
		if(right < heap.size() && heap[right]> heap[largest]) largest=right;

		if(largest!=i)
		{
			swap(heap[largest],heap[i]);
			max_heapify(largest);
		}
	}
	void make_heap(const int &size)
	{
		for(int i=size/2;i>=0;i--)
			max_heapify(i);
	}

	public:

	max_heap(){}
	max_heap(T *start,T *end)
	{
		for(int *it=start;it<end;it++)heap.push_back(*it);
		make_heap(end-start);
	}
	void push(const T &key)
	{
		heap.push_back(key);
		int i=heap.size()-1,p;
		while(i)
		{
			p=PARENT(i);
			if(heap[p]>=heap[i]) break;
			swap(heap[p],heap[i]);
			i=p;
		}
	}
	inline T top()
	{
		return heap[0];
	}
	void pop()
	{
		heap[0]=heap[heap.size()-1];
		heap.erase(heap.end()-1);
		max_heapify(0);
	}
	void print_heap()
	{
		for(int i=0;i<heap.size();i++)
			printf("%d ",heap[i]);
		puts("");
	}
};

int main()
{

	return 0;
}