Implementing Heap Sort in C language

heapsort.c

// Implementing Heap Sort in C language
#include<stdio.h>
void heap(int *a, int n);
void create_heap(int *a, int n);
void main()
{
   int a[50],i,n;
   printf("Enter the limits: ");
   scanf("%d",&n);
   printf("Enter the elements: ");
   for(i=0;i<n;i++)
      scanf("%d",&a[i]);
   heap(a,n);
   printf("The sorted list is...\n");
   for(i=0;i<n;i++)
      printf("%d\n",a[i]);
}
void create_heap(int *a, int n)
{
   int i,j,q,key;
   for(q=1;q<n;q++)
   {
      i=q;
      key=a[q];
      j=(int)(i/2); //Emphasizing the need for integer division
      while((i>0)&&(key>a[j]))
      {
         a[i]=a[j];
         i=j;
         j=(int)(i/2);
         if(j<0)
            j=0;
      }
      a[i]=key;
   }
}
void heap(int *a, int n)
{
   int i,j,q,key,temp;
   create_heap(a,n);
   for(q=n-1;q>=1;q--)
   {
      temp=a[0];
      a[0]=a[q];
      a[q]=temp;
      i=0;
      key=a[0];
      j=1;
      if((j+1)<q)
      if(a[j+1]>a[j])
         j++;
      while((j<=(q-1))&&(a[j]>key))
      {
         a[i]=a[j];
         i=j;
         j=2*i;
         if((j+1)<q)
            if(a[j+1]>a[j])
               j++;
            else if(j>n-1)
         j=n-1;
         a[i]=key;
      }
   }
}