heap_sort_Sanjoy

#include <stdio.h>
#include <conio.h>

int a[20];
int n;
int dummy;
void display()
{
     int i;
     for(i = 0;i < n;i++)
     printf("%d ",a[i]);

}

void build_heap(int k)
{
     int i;
     for(i = k / 2;i >= 0;i--)
     {
          max_heapify(i,k);
     }
}

max_heapify(int i,int size)
{
     int rc,lc,max,idx,temp;

     max = a[i];
     idx = i;
     rc = i * 2 + 2;
     lc = i * 2 + 1;

     if(lc >= size)
           return;
     else
     {
           if(a[i] < a[lc])
           {
                   max = a[lc];
                   idx = lc;
           }
           if(rc < size)
           {
                 if(max < a[rc])
                 {
                    max = a[lc];
                    idx = rc;
                 }
           }
                if(idx != i)
                    {
                          temp = a[i];
                          a[i] = a[idx];
                          a[idx] = temp;

                          max_heapify(idx,size);
                    }
     }
}

heap_sort()
{
     int temp,i;

     while(n != 0)
     {
               temp = a[0];
               a[0] = a[n - 1];
               a[n - 1] = temp;

               n--;
              build_heap(n);
     }
     for(i = 0;i < dummy;i++)
     printf("%d ",a[i]);
}

int main()
{
     int  i,inc,dec,incr,decr,found=1;
         printf("\n enter number of elements ");
         scanf("%d",&n);
         dummy = n;
         printf("\n enter the numbers: ");
         for(i = 0;i < n; i++)
         scanf("%d",&a[i]);

         display();
         printf("\n heap is\n");
        build_heap(n);

         display();

        printf("\nsorted list is: ");
       heap_sort();

         printf("\n enter the value you want to increase : ");
         scanf("%d",&inc);

         for(i=0;i<dummy;i++)
         {
                if(a[i] == inc)
                {
                        found = 1;
                        break;
                }
         }

         if(found != 1)
         printf("\nelement does not exist in the heap!\n");
         else
         {
             printf("\n enter the value : ");
             scanf("%d",&incr);

             if(a[i] > incr)
                     printf("\nentered number is smaller than actual!");
             else
             {
                      for(i=0;i<dummy;i++)
                      {
                            if(a[i] == inc)
                            break;
                      }

                      a[i] = incr;
                      build_heap(dummy);

                      found = 0;

                          for(i = 0;i < dummy;i++)
                           printf("%d ",a[i]);
             }
         }

       // imcrease ends

        printf("\n enter the value you want to decrease : ");
         scanf("%d",&dec);

         for(i=0;i<dummy;i++)
         {
                if(a[i] == dec)
                {
                        found = 1;
                        break;
                }
         }

         if(found != 1)
         printf("\nelement does not exist in the heap!\n");
         else
         {
             printf("\n enter the value : ");
             scanf("%d",&decr);

             if(a[i] < decr)
                     printf("\nentered number is greater than actual!");
             else
             {
                      for(i=0;i<dummy;i++)
                      {
                            if(a[i] == dec)
                            break;
                      }

                      a[i] = decr;
                      build_heap(dummy);

                      found = 0;

                          for(i = 0;i < dummy;i++)
                           printf("%d ",a[i]);
             }
         }

         getch();
         return 0;
}