MaxHeap.cpp

#include <iostream>
using namespace std;

void upHeapify(int *heap, int index)
{
    int parentIndex = (index - 1) / 2;
    int temp;
    while (parentIndex >= 0 && heap[parentIndex] < heap[index])
    {
        temp = heap[parentIndex];
        heap[parentIndex] = heap[index];
        heap[index] = temp;
        index = parentIndex;
        parentIndex = (index - 1) / 2;
    }
}
void downHeapify(int *heap,int size)
{
    int LChild;
    int RChild;
    int largest;
    int temp;
    int i = 0;
    while (true)
    {
        LChild = 2 * i + 1;
        RChild = 2 * i + 2;
        largest = i;

        if (LChild < size && heap[LChild] != -1 && heap[LChild] > heap[largest])
        {
            largest = LChild;
        }

        if (RChild < size && heap[RChild] != -1 && heap[RChild] > heap[largest])
        {
            largest = RChild;
        }

        if (largest == i)
            break;
        temp = heap[i];
        heap[i] = heap[largest];
        heap[largest] = temp;

        i = largest;
    }
}
void insert(int *heap, int size)
{
    int value;
    for (int i = 0; i < size; i++)
    {
        cout << "Enter any number: ";
        cin >> value;
        heap[i] = value;
        if (i != 0)
        {
            upHeapify(heap, i);
        }
    }
}
void Delete(int *heap,int size)
{
    int i = 0;
    int temp;
    while (i < size)
    {
        if (heap[i] == -1)
        {
            break;
        }
        i++;
    }
    i--;
    temp = heap[i];
    heap[i] = heap[0];
    heap[0] = temp;
    heap[i] = -1;
    downHeapify(heap,size);
}
int main(int argc, char const *argv[])
{
    int heap[10];
    int size = sizeof(heap) / sizeof(int);
    //initializing heap
    for (size_t i = 0; i < size; i++)
    {
        heap[i] = -1;
    }
    insert(heap, size);
    //Delete(heap,size);
    // for displaying the heap
    for (size_t i = 0; i < size; i++)
    {
        cout << heap[i] << " ";
    }

    return 0;
}