读书共享 Primer Plus C-part11

Posted 2020-09-28 刘传武

第十四章结构和其他数据形式

关于fread以及fwrite

• fread(char* buff,int size,int count,FILE* fp)
• fwrite(char* buff,int size,int count,FILE* fp)

#include<stdio.h>
#include<string.h>

typedef struct book_s
{
 int count;
 char name[100];
 char author[100];
 float price;

}Book;

int main()
{
   Book books[3] ;
   strcpy(books[0].name,"liuchuanwu0" );
   strcpy(books[0].author,"liu chuan wu 0");
   books[0].price = 1.00;

   strcpy(books[1].name,"liuchuanwu1" );
   strcpy(books[1].author,"liu chuan wu 1");
   books[1].price = 1.00;

   strcpy(books[2].name,"liuchuanwu2" );
   strcpy(books[2].author,"liu chuan wu 2");
   books[2].price = 1.02;

   FILE * fp =fopen("./book.list","a+");

   int index ;

  for(index=0;index<3;index++)
  {
   fwrite(&books[index],sizeof(Book),1,fp);
  }

  memset(&books[2],0,sizeof(Book));
  printf("%s \n",books[2].name);
  rewind(fp) ;
  fread(&books[2],sizeof(Book),1,fp);
  printf("%s \n",books[2].name);

}

结果如下：–结构体可以正常的转存入文件，且vim查看存在乱码，但是可以正常的读写 
linux:/home/lcw/code # ./a.out

liuchuanwu0 
linux:/home/lcw/code # cat book.list 
p?Kliuchuanwu0¢ÿÿÿÿ¢p¢¢D.ι 
¶?¸@ 
liu chuan wu 0?h¢.N=