SORTING TECHNIQUES:-QUICK SORT

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

struct stack
{
 int low, high;
}; 

void main()
{
 int a[50];
 int n;
 clrscr();
 printf("\nEnter n: ");
 scanf("%d",&n);
 read_data(a,n);
 a[n]=9999;
 printf("\nBefore sort :");
 print_data(a,n);
 qck_srt(a,n);
    printf("\nAfter sort :");
    print_data(a,n);
}

int read_data(int a[],int max)
{
 int i;
 printf("\nEnter %d values \n",max);
 for(i=0; i < max; i++)
 {
  scanf("%d",&a[i]);
 }
 return;
}

int print_data(int a[],int max)
{
 int i;
 for(i=0; i < max; i++)
 {
  printf("%4d",a[i]);
 }
 return;
}

int qck_srt(int a[], int n)
{
 struct stack s[50];
 int top;
 int i, j, k, l, h;
 int t;

 //... Initialize Stack
 top = -1;

 //... Push First Position
 top++;
 s[top].low = 0;
 s[top].high = n - 1;

 //... While Stack is not Empty do the following
 while( top != -1 )
 {
  //... Pop top Partition
  l = s[top].low;
  h = s[top].high;
  top--;
  if(l >= h )
  {
   continue;
        }
  k = a[l];
  i = l;
  j = h + 1;
  while( i < j )
  {
   while( i < h && a[i] <= k )
   {
    i++;
   }
   while( j > l && a[j] >= k )
   {
    j--;
   }
   if( i < j )
   {
    t = a[i];
    a[i] = a[j];
    a[j] = t;
   } // if
  } // while
  if(l != j)
  {
   t = a[l];
   a[l] = a[j];
   a[j] = t;
  } // if

  //... Push Right Partition
  top++;
  s[top].low = j + 1;
  s[top].high = h;

  //... Push Left Partition
  top++;
  s[top].low = l;
  s[top].high = j - 1;
 } // while
 return;
} // qck_srt