c - 如何将二进制文件读入C中的结构

Question

我有一个名为 的结构产品 我试图从二进制文件中读取以填充此函数:

void reading(FILE *fp){

  Product *obuff = malloc(sizeof(Product));
  fread(obuff->code, sizeof(obuff->code), 1, fp);
  fread(obuff->name, sizeof(obuff->name), 1, fp);
  fread(obuff->quantity, sizeof(obuff->quantity), 1, fp);
  fread(obuff->price, sizeof(obuff->price), 1, fp);   

  printf("%s %s %d %.2f\n", obuff.code, obuff.name, obuff.quantity, obuff.price);
}

当我尝试编译时，我收到错误消息，说由于错误的数据类型而无法传递参数。有没有办法从二进制文件中读取结构，或者我只是在这里做错了什么？

结构:

#pragma pack(2)
struct product {
   char code[15];
   char name[50];
   short int quantity;
   double price;
};
#pragma pack()

typedef struct product Product;

Answer 1

您必须传递指针才能拥有 fread()读取数据。

void reading(FILE *fp){

  Product *obuff = malloc(sizeof(Product));
  fread(&obuff->code, sizeof(obuff->code), 1, fp);
  fread(&obuff->name, sizeof(obuff->name), 1, fp);
  fread(&obuff->quantity, sizeof(obuff->quantity), 1, fp);
  fread(&obuff->price, sizeof(obuff->price), 1, fp);

  printf("%s %s %d %.2f\n", obuff->code, obuff->name, obuff->quantity, obuff->price);
  free(obuff); /* free whatever you allocated after finished using them */
}