郁闷的实型数据？（能解释一下吗？）

#include "stdio.h"
#define size 100
struct student
{float num;
}stud[size];
main()
{int i;
FILE *fp;
for (i=0;i<size;i++)
      scanf("%f",&stud[i].num);
if ((fp=fopen("t1_dat","wb"))==NULL)
    {printf("cannot open file\n");
     exit(0);
    }
for (i=0;i<size;i++)
     if (fwrite(&stud[i],sizeof(struct student),1,fp)!=1)
  printf("file writer error\n");
}
程序运行后提示：scanf:float point formats not linked abormal program termination
为什么呢？怎么改才能将实行数据写入文件中呢？
谢了！
----------------解决方案--------------------------------------------------------
为什么要定义这样的结构体？就一个域？

#include "stdio.h"
#define size 100
struct student
{float num;
}stud[size];
main()
{int i;float f;
FILE *fp;
for (i=0;i<size;i++)
     { scanf("%f",&f); stud[i].num=f;}
if ((fp=fopen("t1_dat","wb"))==NULL)
    {printf("cannot open file\n");
     exit(0);
    }
for (i=0;i<size;i++)
     if (fwrite(&stud[i],sizeof(struct student),1,fp)!=1)
  printf("file writer error\n");
}
----------------解决方案--------------------------------------------------------