快速排序

#include
using namespace std;
int a[100];
int n;
int partition(int r[],int low,int high)// 这只是一次划分，还要进行递归排序。 
{
   r[0] = r[low];
   int pivotkey = r[low];
   while(low < high)
   {
		 while(low < high && r[high] >= pivotkey) --high;
		 if(low < high) r[low++] = r[high];
		 while(low < high && r[low] <= pivotkey)   ++low;
		 if(low < high) r[high--] = r[low];
   }
   r[low] = r[0];
   return low;
}
void Qsort(int  r[],int s,int t)
{
	if(s>n)
	{
		
		for(int i = 1; i <= n; i ++)
				cin>>a[i];
		Qsort(a,1,n); 
		for(int i = 1; i <= n; i ++)
		       cout<