快速排序

#include <iostream>
using namespace std;
int a[50];

int Partion(int begin, int end)
{
    int compare=a[begin], left =begin,right = end;
    if(left >right)
        return -1;
    while (left <right)
    {
        while ((left <right) && a[right]>=compare)
            right--;
        a[left++] = a[right];
        while ((left <right) &&(a[left] <compare))
            left++;
        a[right--] = a[left];
    }
    a[left] = compare;
    return left;
}

void qs(int begin,int end)
{
    if (begin < end)
    {
        int split = Partion(begin, end);
        qs(begin,split-1);
        qs(split+1,end);
    }
}

int main()
{
    int i;
    for (i =0; i< 50; i++)
    {
        a[i] =50-i;
    }
    cout<<"排序前"<<endl;
    for (i= 0; i<50; i++)
    {
        cout<<"a["<<i<<"] = "<<a[i]<<endl;
    }
    cout<<"排序後"<<endl;
    qs(0,49);
    for (i=0; i<50; i++)
    {
        cout<<"a["<<i<<"] = "<<a[i]<<endl;
    }
    return 0;
}