C程序 - 文件 - FWRITE [英] C Programming - File - fwrite

问题描述

我有关于编程和文件的问题。

I've got a question regarding programming and files.

while(current!=NULL)
{
  if(current->Id_Doctor!='\0')
  {
    current=current->next;
    id_doc=(current->Id_Doctor);
  }
  if(current->Id_Doctor=='\0')
  {
    id_doc=id_doc+1;
    printf("%d", id_doc);
    break;
  }
}
fwrite(&id_doc, sizeof(char), 1, Archivo);

我不知道为什么，但它是不是在所谓的Archivo'二进制文件写入id_doc的价值... ...可能是什么问题呢？
我加id_doc的printf和值为printed..I真的不知道

I dont know why but it aint writing the value of id_doc on the binary file called 'Archivo'...what could be the problem? I added a printf of id_doc and the value was printed..I really dont know

好吧，继承人的全code（更少）：

Ok, heres the full code(more-less):

struct Medico
{
  int Id_Doctor;
  int Estado;
  char Nombre[60];
  char Clave_Acceso[20];
  char Especialidad[40]; 
  struct Medico *next;
};
void Dar_Alta_Med (int estado);
void MenuPrincipal(char enta);
int main(void)
{
  char enta;
  MenuPrincipal(enta);
}
void Dar_Alta_Med(int estado)
{
  struct Medico * head = NULL;
  struct Medico * prev, *current;
  char nombre_doc[60], especialida[40], password[20];
  int id_doc=0, estado_doc=1;
  FILE *Archivo;
 const char *md1="\n<md>\n";
  const char *id_doc1="<id_doctor> ";
 Archivo=fopen("md.dat", "ab+");
  fwrite(md1, 1, strlen(md1), Archivo);
  fwrite(id_doc1, 1, strlen(id_doc1), Archivo);
  current = (struct Medico *) malloc (sizeof(struct Medico));
  current->Id_Doctor=id_doc; 
  while(current!=NULL)
    {
      if(current->Id_Doctor!='\0')
    {
      current=current->next;
      id_doc=(current->Id_Doctor);
    }
      else
    {
      id_doc=id_doc+1;
      printf("%d", id_doc);
      break;
    }
    }
  fwrite(&id_doc, sizeof(id_doc), 1, Archivo);
  printf("Ingresa el nombre del Doctor a dar de alta: ");
  fclose(Archivo);
}

林垂死这里，请大家帮帮忙：/

Im dying here, please help :/

推荐答案

三件事情：

• 请确保您的fopen是成功的。

• Make sure your fopen is successful.

Archivo=fopen("md.dat", "ab+");
if (Archivo == NULL)
{
     perror("Failed to open file Archivo");
     ...
}

请确保您检查您的fwrite的成功。

Make sure you are checking the success of your fwrite's.

if (fwrite(&id_doc, sizeof(id_doc), 1, Archivo) < 1)    
{    
     perror("Failed to write to file Archivo");
     ... 
}

请确保您有FCLOSE正确关闭文件。

Make sure you have a fclose to close the file properly.

if (fclose(Archivo) != 0)    
{    
    perror("Failed to close file Archivo");     
    ...
}

现在，你已经发表您的code的全样本我想我应该问，如果错误检查刚走出去简洁？如果没有，你应该考虑增加它。

Now that you've post a full sample of your code I guess I should ask if error checking is just left out for brevity? If not, you should think about adding it.

如果您期望id_doc的价值将在输出文件显示格式，你必须为int转换成字符串（使用的snprintf或类似），并写入字符串到输出文件来代替。

If you're expecting the value of id_doc to be in display format in the output file you'll have to convert the int to a string (using snprintf or similar) and write the string to the output file instead.

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