快速排序--陈惠南版

#include<iostream>
using namespace std;
int b[]={2,5,3,6,1,7,9};
void qsort(int a[],int left,int right)  
{  
    int i,j;  
    if(left<right){  
        i=left;  
        j=right+1;  
        do{  
            do i++;while (a[i]<a[left]);  
            do j--;while (a[j]>a[left]);  
            if(i<j)  
                swap(a[i],a[j]);  
        }while(i<j);  
        swap(a[left],a[j]);  
        qsort(a,left,j-1);  
        qsort(a,j+1,right);  
    }  
}
int main()
{
	qsort(b,0,6);
	for(int i=0;i<6;i++)
		cout<<b[i]<<" ";
	return 0;
}

#include <iostream>
#include <stack>
using namespace std;

int partition(double* a, int left, int right)  
{  
	int i,j;    
	if(left<right){    
		i=left;    
		j=right+1;    
		do{    
			do i++;while (a[i]<a[left]);    
			do j--;while (a[j]>a[left]);    
			if(i<j)    
				swap(a[i],a[j]);    
		}while(i<j);    
		swap(a[left],a[j]);   
		return j;  
	} 
}
void quickSort(double* a, int left, int right)
{
	stack<int> t;
	if(left<right)
	{
		int p = partition(a, left, right);
		if (p-1>left)
		{
			t.push(left);
			t.push(p-1);
		}
		if (p+1<right)
		{
			t.push(p+1);
			t.push(right);
		}
		while(!t.empty())
		{
			int r = t.top();
			t.pop();
			int l = t.top();
			t.pop();
			p = partition(a, l, r);
			if (p-1>l)
			{
				t.push(l);
				t.push(p-1);
			}
			if (p+1<r)
			{
				t.push(p+1);
				t.push(r);
			}
		}
	}
}
int main()
{
	double a[]={2,5,3,6,1,7,9};
	quickSort(a,0,6);
	for(int i=0;i<7;i++)
		cout<<a[i]<<" ";
	return 0;
}