heap_sort

#include <stdio.h>
#include <stdlib.h>

int heap_size;

void heap_sort(int *arr, int size)
{
   buildheap(arr);
   int j,temp;
   for(j=size;j>=1;j--)
   {
       temp = arr[j];
       arr[j] = arr[0];
       arr[0] = temp;
       heap_size--;
       max_heapify(arr,0);
   }
}

void buildheap(int*arr)
{
    int j;
    for(j=heap_size/2;j>=0;j--)
    {
        max_heapify(arr,j);
    }
}

void max_heapify(int *arr, int i)
{
    int left = 2*i +1;
    int right = 2*i +2;
    int largest =i,temp;
    if(left<=heap_size && arr[left]>arr[i])
    {
        largest = left;
    }
    if(right<=heap_size && arr[right] > arr[largest])
    {
        largest = right;
    }
    if(largest!=i)
    {
        temp = arr[largest];
        arr[largest] = arr[i];
        arr[i] = temp;
        max_heapify(arr, largest);
    }
}

int main()
{
    int size,i;
    printf("Enter the size of array : ");
    scanf("%d",&size);
    int *arr;
    arr=(int*)malloc(size*sizeof(int));
    printf("\nEnter the elements \n");
    for(i=0;i<size;i++)
    {
        scanf("%d",&arr[i]);
    }
    printf("\nArray is\n");
    for(i=0;i<size;i++)
        printf("%d\t",arr[i]);
    printf("\n");
    heap_size = size;
    heap_sort(arr,size);
    printf("\n\nSorted array is\n\n");
    for(i=0;i<size;i++)
        printf("%d\t",arr[i]);
    return 0;
}