C语言：将结构体存放到文件中

#include <stdio.h>
#include <stdlib.h>
#define MAXTLEN 70
#define MAXALEN 70
#define MAXBKS 10
struct book{
        char title[MAXTLEN];
        char author[MAXALEN];
        float value;
};

int main(){
        struct book library[MAXBKS];    //图书馆
        int count = , index, filecount;
        int size = sizeof(struct book); //这点值得注意
        FILE *pbooks;
        if((pbooks = fopen("book.dat","a+b")) == NULL){
                fputs("Can not open book.dat file\n", stderr);
                exit();
        }
        rewind(pbooks);
        while(count < MAXBKS && fread(&library[count],size,,pbooks) == ){
                if(count == ){
                        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();
        }
        puts("please add the new book, title:");
        while(count < MAXBKS && gets(library[count].title) != NULL && library[count].title[] != '\0'){
                puts("the author:");
                gets(library[count].author);
                puts("the value:");
                scanf("%f",&library[count++].value);
                while(getchar() != '\n'){
                        continue;
                }
                if(count < MAXBKS){
                        puts("---continue---");
                }
        }
        if(count > ){
                puts("Here is the list of your books:");
                for(index = ; 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 ;
}

Current contents of book.dat:
C语言权威指南 by jimmy: $68.00
PHP项目大全 by jimmy: $99.90
please add the new book, title: