快速排序(快排)算法的C++两种实现

快排算法在分治的时候有两种实现，一种实现是从两边到中间(partition)，另一种实现是从一边到另一边(partition2)。我用一个100000数组测试发现前一种实现运行速度快一些。

这两种的C++实现如下： （注：我用的代码风格是gnu的代码风格）

bool sort::qsort(int *ini, int start, int end){ // sort the array ini by ascending order  int tmp=0;  int mid=0;  if (end < start){    return false;  }else if(end == start){    if(ini[start] > ini[end])      {tmp = ini[start];ini[start] = ini[end];ini[end] = tmp;      }    return true;  }else{   // when start is less end;    mid = this->partition2(ini, start, end);     // the partition fun. can either be partiton or partiton2.    if(mid == start && qsort(ini,mid+1,end))      return true;    if( mid == end && qsort(ini,start,mid-1))      return true;    if(qsort(ini,start,mid-1) && qsort(ini,mid+1,end))      return true;    return true;  }}int sort::partition(int *ini, int start, int end){   // the main body for partition which from edge to middle  int key=0;  int i=start;  int j=end;  int tmp = 0;  key = ini[i];  while(i!=j)    {      while(key <= ini[j] && i < j)j--;      // exchange value, from right to left      tmp = ini[i];      ini[i] = ini[j];      ini[j] = tmp;      while(key >= ini[i] && i < j)i++;      // exchange value, from left to right      tmp = ini[i];      ini[i] = ini[j];      ini[j] = tmp;    }  return i;}int sort::partition2(int *ini, int start, int end){   // the main body for partition which from end to begin  int key = ini[end];  int i = start - 1;// suppose the mid pos is i+1  int j=start;  int tmp = 0;  for(;j<end;j++)    {      if(ini[j] < key ){  i++;  tmp = ini[i];  ini[i] = ini[j];  ini[j] = tmp;}    }  ini[end] = ini[i+1];  ini[i+1] = key;  return i+1;}