C庫函數使用集

1 qsort()函數使用#include <stdio.h>
#include <stdlib.h>
typedef struct PLANT {
    int num;
    char name[13];
    
}Plant;

int Mycompare(const void *lth,const void *rth)//形參應該是const void*類型
{
    Plant* lpl=(Plant*)lth;
    Plant* rpl=(Plant*)rth;
    return lpl->num-rpl->num;
}
int main(void)
{
    int i,n;
    Plant plant[5]={{3,"wangtian"},{1,"wangshuo"},{5,"wangru"},{2,"wangfang"},{4,"wangxiao"}};
    
    for(i=0;i<5;i++)
        printf("%d\t%s\n",plant[i].num,plant[i].name);

    qsort(plant,5,sizeof(Plant),Mycompare);

    printf("\n");

    for(i=0;i<5;i++)//輸出排好序後的結構體數組
        printf("%d\t%s\n",plant[i].num,plant[i].name);
    printf("%d\n",sizeof(Plant));

fflush(stdin);//重新整理緩衝區
  char q;
  scanf("%c",&q);
  return 0;
}