请问为什么我修改缴费文件的信息只能修改第一条？具体代码如下，求大神解答！谢谢！！！！

Question

void jiaofei()

{ FILE *f;

  if((f=fopen("E://jiaofei.txt","a"))!=NULL)

  {

  int i;

  system("cls");

  printf("您一共要缴的费用为5000元！\n");

  printf("请输入您的学号：\n");

  scanf("%s",yonghu[0].num);

  printf("请输入您的姓名：\n");

  scanf("%s",yonghu[0].name);

  system("cls");

  printf("请输入您要缴费的金额:\n");

  scanf("%d",&yonghu[0].x);

  yonghu[0].y=5000-yonghu[0].x;

  if(yonghu[0].x>5000)

 {printf("您所输入的金额大于您所应当缴费的金额，请重新输入缴费金额!\n");}

  else 

  printf("缴费成功！\n");

  printf("您还应当缴的费用为%d",yonghu[0].y);

  fprintf(f,"%s ",yonghu[0].num);

  fprintf(f,"%s ",yonghu[0].name);

  fprintf(f,"%d ",yonghu[0].x);

  fprintf(f,"%d\n",yonghu[0].y);

  fclose(f);

  system("pause");

  return;

  }

}

void bujiao()

{ int i,n;

int m=0;

char num[20];

FILE *f;

printf("请输入补缴学费学生的学号:\n");

scanf("%s",num);

f=fopen("E://jiaofei.txt","r");

for(i=0; !feof(f) && i<=10000; i++) {

if(fscanf(f,"%s",yonghu[i].num)!=1)  break;

if(fscanf(f,"%s",yonghu[i].name)!=1) break;

if(fscanf(f,"%d",&yonghu[i].x)!=1)   break;

if(fscanf(f,"%d",&yonghu[i].y)!=1)   break;

if(strcmp(num,yonghu[i].num)==0) {

m=1;

printf("学号:%s ",yonghu[i].num);

printf("姓名:%s ",yonghu[i].name);

printf("已缴学费:%d ",yonghu[i].x);

printf("未缴学费:%d\n",yonghu[i].y);

}

}

if(m==0)

printf("查无此人！");

//scanf("%*s");

//fclose(f);

if((f=fopen("E://jiaofei.txt","r+"))!=NULL)

{

printf("请输入您要补缴学费的金额：\n");

scanf("%d",&yonghu[0].x1);

    if(yonghu[0].x1>yonghu[0].y)

    {printf("您所输入的金额大于您所应当缴费的金额，请重新输入缴费金额!\n");}

  else 

    printf("补缴成功！\n");

    printf("您还应当缴的费用为%d",5000-yonghu[0].x-yonghu[0].x1);

     fprintf(f,"%s ",yonghu[0].num);

     fprintf(f,"%s ",yonghu[0].name);

     fprintf(f,"%d ",yonghu[0].x+yonghu[0].x1);

     fprintf(f,"%d\n",5000-yonghu[0].x-yonghu[0].x1);

     fclose(f);

}

}

Answer 1

你是声明了结构体类型吗？方便的话把源代码贴出来！