qsort库函数排序

#include<stdio.h>
#include<stdlib.h>
struct Stu
{
  char name[20];
  int age;
};
int cmp_int(const void* e1, const void* e2)
{
  return *(int*)e1 - *(int*)e2;
}
int cmp_float(const void* e1, const void* e2)
{
  return (int)(*(float*)e1 - *(float*)e2);
}
//结构体排序有不同排序方法，每个人的标准不同，有人是名字，有人是姓名
int cmp_stu_age(const void* e1, const void* e2)
{
  return ((struct Stu*)e1)->age - ((struct Stu*)e2)->age;
}
int cmp_stu_name(const void* e1, const void* e2)
{
  //名字比较就是比较字符串
  //字符串比较不能直接用<>=来比较，应该用strcmp来比较
  return strcmp(((struct Stu*)e1)->name , ((struct Stu*)e2)->name);
}
void test_int()
{
  int arr[10] = { 0,5,6,3,5,9,6,5,3,9 };
  int sz = sizeof(arr) / sizeof(arr[0]);
  qsort(arr, sz, sizeof(arr[0]), cmp_int);
  int i = 0;
  for (i = 0; i < sz; i++)
  {
    printf("%2d ", arr[i]);
  }
  printf("\n");
}
void test_float()
{
  float arr[10] = { 0.0,5.0,6.0,3.0,5.1,9.0,6.3,5.6,3.3,9.5 };
  int sz = sizeof(arr) / sizeof(arr[0]);
  qsort(arr, sz, sizeof(arr[0]), cmp_float);
  int i = 0;
  for (i = 0; i < sz; i++)
  {
    printf("%f ", arr[i]);
  }
  printf("\n");
}
void test_stu_age()
{
  struct Stu s[3] = { {"zhuangsan",20},{"lisi",21},{"wangwu",10} };
  int sz = sizeof(s) / sizeof(s[0]);
  qsort(s, sz, sizeof(s[0]), cmp_stu_age);
  int i = 0;
  for (i = 0; i < sz; i++)
  {
    printf("%s  ", (&s[i])->name);
    printf("%d  ", (&s[i])->age);
  }
  printf("\n");
}
void test_stu_name()
{
  struct Stu s[3] = { {"zhuangsan",20},{"lisi",21},{"wangwu",10} };
  int sz = sizeof(s) / sizeof(s[0]);
  qsort(s, sz, sizeof(s[0]), cmp_stu_name);
  int i = 0;
  for (i = 0; i < sz; i++)
  {
    printf("%s  ", (&s[i])->name);
    printf("%d  ", (&s[i])->age);
  }
  printf("\n");
}
int main()
{
  test_int();
  test_float();
  test_stu_age();
  test_stu_name();
  return 0;
}

#include<stdio.h>
struct Stu
{
  char name[20];
  int age;
};
//自己写一个万能交换函数
void Swap(char* buf1, char* buf2,int width)
{
  size_t i = 0;
  for (i = 0; i < width; i++)
  {
    char tmp = *buf1;
    *buf1 = *buf2;
    *buf2 = tmp;
    buf1++;
    buf2++;
  }
}
//自己写一个冒泡函数,使用回调函数实现一个通用的冒泡排序函数
BubbleSort(void* base, int num, size_t width, int (*cmp)(const void* e1, const void* e2))
{
  int i = 0;
  //趟数
  for (i = 0; i < num - 1; i++)
  {
    //比较的对数
    int j = 0;
    for (j = 0; j < num - 1 - i; j++)
    {
      if (cmp((char*)base+j*width,(char*)base+(j+1)*width) > 0)
      {
        //交换
        Swap((char*)base + j * width, (char*)base + (j + 1) * width,width);
      }
    }
  }
}
int cmp_int(const void* e1, const void* e2)
{
  return *(int*)e1 - *(int*)e2;
}
int cmp_float(const void* e1, const void* e2)
{
  return (int)(*(float*)e1 - *(float*)e2);
}
int cmp_stu_age(const void* e1, const void* e2)
{
  return ((struct Stu*)e1)->age - ((struct Stu*)e2)->age;
}
int cmp_stu_name(const void* e1, const void* e2)
{
  //名字比较就是比较字符串
  //字符串比较不能直接用<>=来比较，应该用strcmp来比较
  return strcmp(((struct Stu*)e1)->name, ((struct Stu*)e2)->name);
}
void test_int()
{
  int arr[10] = { 0,5,6,3,5,9,6,5,3,9 };
  int sz = sizeof(arr) / sizeof(arr[0]);
  BubbleSort(arr, sz, sizeof(arr[0]), cmp_int);
  int i = 0;
  for (i = 0; i < sz; i++)
  {
    printf("%2d ", arr[i]);
  }
  printf("\n");
}
void test_float()
{
  float arr[10] = { 0.0,5.0,6.0,3.0,5.1,9.0,6.3,5.6,3.3,9.5 };
  int sz = sizeof(arr) / sizeof(arr[0]);
  BubbleSort(arr, sz, sizeof(arr[0]), cmp_float);
  int i = 0;
  for (i = 0; i < sz; i++)
  {
    printf("%f ", arr[i]);
  }
  printf("\n");
}
void test_stu_age()
{
  struct Stu s[3] = { {"zhuangsan",20},{"lisi",21},{"wangwu",10} };
  int sz = sizeof(s) / sizeof(s[0]);
  BubbleSort(s, sz, sizeof(s[0]), cmp_stu_age);
  int i = 0;
  for (i = 0; i < sz; i++)
  {
    printf("%s  ", (&s[i])->name);
    printf("%d  ", (&s[i])->age);
  }
  printf("\n");
}
void test_stu_name()
{
  struct Stu s[3] = { {"zhuangsan",20},{"lisi",21},{"wangwu",10} };
  int sz = sizeof(s) / sizeof(s[0]);
  BubbleSort(s, sz, sizeof(s[0]), cmp_stu_name);
  int i = 0;
  for (i = 0; i < sz; i++)
  {
    printf("%s  ", (&s[i])->name);
    printf("%d  ", (&s[i])->age);
  }
  printf("\n");
}
int main()
{
  test_int();
  test_float();
  test_stu_age();
  test_stu_name();
  return 0;
}