用C写一个图书管理系统，要求用户输入图书的各个信息，用户再输入0，代表查看信息，然后选择查看的id，然后输出该本书的信息，输入1代表录入一本书的信息，信息包括id号、书名、作者名、价格和数量等

用C写一个图书管理系统，要求用户输入图书的各个信息，用户再输入0，代表查看信息，然后选择查看的id，然后输出该本书的信息，输入1代表录入一本书的信息，信息包括id号、书名、作者名、价格和数量等；系统的主要功能包括：图书信息的创建，保存图书信息.

#include 
#include 
#include 

struct Book {
    int id;
    char title[100];
    char author[100];
    float price;
    int quantity;
};

struct BookManagementSystem {
    struct Book* books;
    int capacity;
    int size;
};

struct BookManagementSystem* createBookManagementSystem(int capacity) {
    struct BookManagementSystem* bms = (struct BookManagementSystem*)malloc(sizeof(struct BookManagementSystem));
    bms->books = (struct Book*)malloc(capacity * sizeof(struct Book));
    bms->capacity = capacity;
    bms->size = 0;
    return bms;
}

void addBook(struct BookManagementSystem* bms, int id, char* title, char* author, float price, int quantity) {
    if (bms->size < bms->capacity) {
        struct Book* newBook = &(bms->books[bms->size]);
        newBook->id = id;
        strcpy(newBook->title, title);
        strcpy(newBook->author, author);
        newBook->price = price;
        newBook->quantity = quantity;
        bms->size++;
    } else {
        printf("Book database is full. Cannot add more books.\n");
    }
}

void displayBookInfo(struct BookManagementSystem* bms, int id) {
    for (int i = 0; i < bms->size; i++) {
        if (bms->books[i].id == id) {
            printf("Book ID: %d\n", bms->books[i].id);
            printf("Title: %s\n", bms->books[i].title);
            printf("Author: %s\n", bms->books[i].author);
            printf("Price: %.2f\n", bms->books[i].price);
            printf("Quantity: %d\n", bms->books[i].quantity);
            return;
        }
    }
    printf("Book with ID %d not found.\n", id);
}

void saveBooksToFile(struct BookManagementSystem* bms, char* filename) {
    FILE *file = fopen(filename, "w");
    if (file != NULL) {
        for (int i = 0; i < bms->size; i++) {
            fprintf(file, "%d,%s,%s,%.2f,%d\n", bms->books[i].id, bms->books[i].title, bms->books[i].author, bms->books[i].price, bms->books[i].quantity);
        }
        fclose(file);
    } else {
        printf("Unable to open file for writing.\n");
    }
}

int main() {
    struct BookManagementSystem* bms = createBookManagementSystem(10);
    int choice;
    int id;
    char title[100];
    char author[100];
    float price;
    int quantity;

    while (1) {
        printf("Enter 0 to view book information, enter 1 to add a new book, or any other number to exit: ");
        scanf("%d", &choice);
        if (choice == 0) {
            printf("Enter the book ID to view: ");
            scanf("%d", &id);
            displayBookInfo(bms, id);
        } else if (choice == 1) {
            printf("Enter book ID: ");
            scanf("%d", &id);
            printf("Enter title: ");
            scanf("%s", title);
            printf("Enter author: ");
            scanf("%s", author);
            printf("Enter price: ");
            scanf("%f", &price);
            printf("Enter quantity: ");
            scanf("%d", &quantity);
            addBook(bms, id, title, author, price, quantity);
        } else {
            break;
        }
    }

    saveBooksToFile(bms, "books.txt");
    free(bms->books);
    free(bms);
    return 0;
}