再次读取文件时,把原来的记录打印了两遍,是fread的问题还是我代码逻辑问题.

Question

以下是代码,代码的逻辑是可以再次读取文件时,可以把原来已经存储的记录输出.
但是出现的问题是,再次读取文件时,会把文件存储的记录输出两遍.
自己调试了好几遍,感觉是代码中红色箭头的逻辑问题...但是不知道为什么这里逻辑会问题
按照道理,第一次如果存储两个记录,文件中存储的结构应该只有两个.重新打开文件时,count++到2时,fread函数读取应该不能再读到数据.
但是编译器还是继续进入while循环,把第一次的两个记录又读取一遍,再输出.
各位大神帮看看
#include
#include
#include
#define MAXTITL 40
#define MAXAUTL 40
#define MAXBKS 10
char s_gets(char *st, int n);
struct book
{
char title[MAXTITL];
char author[MAXAUTL];
float value;
};
int main()
{
struct book library[MAXBKS];
int count =0;
int index, filecount;
FILE *pbooks;
int size = sizeof(struct book);
if ( (pbooks = fopen("C:/JavaTest/book2.dat", "a+b")) == NULL)
{
fputs("Can't open book.dat file\n",stderr);
exit(1);
}
rewind(pbooks);
*>>>>>>> ** while (count < MAXBKS && fread(&library[count], size, 1, pbooks) == 1 && feof(pbooks) != EOF)
{
if (count == 0)
{
puts("Current contents of book.dat");
}
printf("%s by %s: $%.2f\n",library[count].title,library[count].author, library[count].value);
count++;
}
filecount = count;
if (count == MAXBKS)
{
fputs("The book.dat file is full.",stderr);
exit(2);
}
puts("Please add new book titles.");
puts("Press [enter] at the start of a line to stop.");
while (count < MAXBKS && s_gets(library[count].title,MAXTITL) != NULL && library[count].title[0] != '\0')
{
puts("Now enter the anthor.");
s_gets(library[count].author, MAXAUTL);
puts("Now enter the value.");
scanf("%f", &library[count++].value);
while (getchar() != '\n')
{
continue;
}
if (count < MAXBKS)
{
puts("Enter the next title.");
}
}
if (count >0 )
{
puts("Here is the list of your books:");
for(index = 0; index < count; index++)
{
printf("%s by %s: $%.2f\n",library[index].title,library[index].author, library[index].value);
fwrite(&library[filecount], size, count - filecount , pbooks);
}
}else
{
puts("No books? Too bad.\n");
}
puts("Bye.\n");
fclose(pbooks);
return 0;
}
char* s_gets(char *st, int n)
{
char * ret_val;
char * find;
ret_val = fgets(st, n, stdin);
if (ret_val)
{
find = strchr(st, '\n');
if (find)
{
*find = '\0';
}else
{
while (getchar() != '\n')
{
continue;
}
}
}
return ret_val;
}

Answer 1

https://zhidao.baidu.com/question/495512328414643964.html