C++ qsort 实现

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自己写的C++ STL Algorithm中qsort的实现如下：

void swap(void *a, void *b, int size){    unsigned char *bytesOfA = reinterpret_cast<unsigned char*>(a);    unsigned char *bytesOfB = reinterpret_cast<unsigned char*>(b);    char tmp = 0;    for(int i = 0; i < size; ++i)    {        tmp = *(bytesOfA+i);        *(bytesOfA+i) = *(bytesOfB+i);        *(bytesOfB+i) = tmp;    }}int partition(void *base, int num, int size, int (*comparator)(const void *, const void *)){    int first = 0, end = num-1;    while(first < end)    {        while(first < end && comparator(base+first*size, base+end*size) <= 0)        {            --end;        }        if(first < end)        {            swap(base+first*size, base+end*size, size);            ++first;        }        while(first < end && comparator(base+first*size, base+end*size) <= 0)        {            ++first;        }        if(first < end)        {            swap(base+first*size, base+end*size, size);            --end;        }    }    return first;}void qsort(void *base, int num, int size, int (*comparator)(const void *, const void *)){    if(num > 0)    {        int pivot = partition(base, num, size, comparator);        qsort(base, pivot, size, comparator);        qsort(base+(pivot+1)*size, num-pivot-1, size, comparator);    }}

用poj2388题测试，时间、内存比用STL的qsort还要略少一点，可能是数据不大的原因吧，STL里的qsort可以对非常大的内存空间排序，应该是迭代实现的。