排序

　
Quick Sort：

template <class T> struct Qsort
{
    T *a, t;
    void swap (int i, int j) {t=a[i]; a[i]=a[j]; a[j]=t;}
    void operator = (T* v)   {a=v;}

    void sort (int L, int R)        //M=midden, L=left, R=right
    {
        if (L >= R) return;               
        int i, M=L;
        swap (L, (L+R)/2)                        
        for (i=L+1; i<=R; ++i)
            if (a[i] < a[L]) 
                swap (++M, i);  
        swap (L, M);        
        sort (L, M-1); 
        sort (M+1, R);
    }
};

int main ()
{
    int i, a[] = {26, 8, 42, 3, 81, 14, 60, 16, 50, 18};
    int n = sizeof a/ sizeof*a - 1;
    Qsort<int> Q; 
    Q = a;
    Q.sort (0, n);
    for (i=0; i<=n; i++) 
        cout <<" " << a[i];
}