typedef struct book {
char title[20];
 char author[20];
 int pages[10];

} Book;

Book b1 = {"The Zahir","Paulo Coelho",336,0};

while writing this structure into SPIFFS of ESP8266, I am using function

filename.write( (const uint8_t*)&b1, sizeof(b1));

but how can write a single data like name of book into structure of spiffs?