c++ 快速排序

#include<iostream>
using namespace std;

void swap(int &a,int &b)
{
    if(a==b)
        return;
    a=a+b;
    b=a-b;
    a=a-b;
}

int qsort(int *array,int low,int high)
{
    int key=array[low];
    cout<<"key="<<key<<endl;
    while(low < high)
    {
        while(low < high && key <= array[high])
            high--;
        swap(array[low],array[high]);
        
        while(low < high && key >= array[low])
            low++;
        swap(array[low],array[high]);
    }
    cout<<"low="<<low<<endl;
    return low;
}

void quitsort(int *buf,int low,int high)//参数里的low永远都是0，high永远都是sizeof(buf)/sizeof(int)-1
{
    if(low < high)
    {
        int pos=qsort(buf,low,high);

        //qsort(buf,low,key-1);//递归错误！
        //qsort(buf,key+1,high);
        quitsort(buf,low,pos-1);//前面的if(low < high)判断很重要
        quitsort(buf,pos+1,high);
    }
}

void print(int *p,int length)
{
    for(int i=0;i<length;++i)
    {
        cout<<p[i]<<" ";
    }
    cout<<endl;
}

int main()
{
    //int buf[10]={2,3,60,42,8,199,20,5,6,7};
    int buf[6]={5,8,9,16,2,4};
    cout<<"排序前："<<endl;
    print(buf,sizeof(buf)/sizeof(int));
    quitsort(buf,0,sizeof(buf)/sizeof(int)-1);
    cout<<"排序后："<<endl;
    print(buf,sizeof(buf)/sizeof(int));
}

g++ -std=c++11编译