qs

 void quicksort(int start,int end, int a[])
  {
  pivot = start;
  lp = start+1;
  rp = end;
  if(start ==  end)
  	return;
  while(lp<rp)
  {
  while(a[lp]>a[pivot])
    lp++;
  while(a[rp]<a[pivot])
    rp--;
  swap(a[rp],a[lp]);
  }
  swap(a[pivot],a[lp]);
  quicksort(pivot+1,lp,a);
  quicksort(lp+1,end,a);
  
  }