一个快速排序算法代码分享

typedef struct _student
{
 int id;
 char name[30];
}student,*pStudent;

student students[20] =
{
 {13,"狐狸金"},{15,"杜十娘"},{8,"葫芦娃"},{4,"喜羊羊"},
 {14,"叮当猫"},{18,"孙悟空"},{3,"格列佛"},{6,"咖啡猫"},
 {19,"猪八戒"},{11,"程序员"},{5,"鲁滨逊"},{9,"金枪鱼"},
 {10,"马大哈"},{12,"周星星"},{1,"灰太狼"},{2,"唐老鸭"},
 {20,"子虚君"},{16,"乌有君"},{7,"小二郎"},{17,"贾宝玉"},
};

//students[]是需要进行排序的数组，length是students数组的元素个数
void quickSort(student students[],int length)
{
 int i,j,flag = students[0].id;
 student stutemp;
 int t;

 if(length>1)
 {
  for(t=0;t<length;t++)
  {
   printf("%d   ",students[t].id);
  }
  printf("\n");

  //为分区选好分裂点
  for(i=0,j=length-1;i<j;)
  {
   for(;students[i].id<flag;i++);
   for(;students[j].id>flag;j--);

   stutemp.id = students[j].id;
   strcpy(stutemp.name,students[j].name);

   students[j].id = students[i].id;
   strcpy(students[j].name,students[i].name);

   students[i].id = stutemp.id;
   strcpy(students[i].name,stutemp.name);
  }

  //打印排序过程
  for(t=0;t<length;t++)
  {
   printf("%d   ",students[t].id);
  }
  printf("----排序后\n-----------------------------------中轴：%d 中轴下标：%d\n",flag,j);

  //进行分区并对分区进行递归调用quickSort，在原数组空间里进行操作
  quickSort(&students[0],j+1);
  quickSort(&students[j+1],length-j-1);
 }
}

int main()
{
 int i;

 //排序前打印
 printf("排序前：\n");
 for(i=0;i<20;i++)
 {
  printf("%d  %s\t",students[i].id,students[i].name);
  if(!((i+1)%5))
  {
   printf("\n");
  }
 }

 quickSort(students,20);

 //排序后打印
 printf("__________________________________________________________________\n排序后：\n");
 for(i=0;i<20;i++)
 {
  printf("%d  %s\t",students[i].id,students[i].name);
  if(!((i+1)%5))
  {
   printf("\n");
  }
 }

 return 0;
}
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