用C语言写一个图书借阅系统，包括查看图书，添加图书，删除图书，借阅图书，归还图书，用户反馈等功能

好的，下面是一个简单的图书借阅系统的代码实现，包括上述提到的功能：

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

#define MAX_BOOKS 100
#define MAX_USERS 100
#define MAX_BOOK_NAME 50
#define MAX_USER_NAME 20

typedef struct book {
    char name[MAX_BOOK_NAME];
    char author[MAX_USER_NAME];
    char publisher[MAX_USER_NAME];
    int pub_year;
    int isbn;
    float price;
    int available;
} Book;

typedef struct user {
    char name[MAX_USER_NAME];
    int borrowed_books[MAX_BOOKS];
    int borrowed_count;
} User;

Book books[MAX_BOOKS];
int book_count = 0;
User users[MAX_USERS];
int user_count = 0;

void add_book() {
    Book book;

    printf("Enter book name: ");
    scanf("%s", book.name);

    printf("Enter author name: ");
    scanf("%s", book.author);

    printf("Enter publisher name: ");
    scanf("%s", book.publisher);

    printf("Enter publication year: ");
    scanf("%d", &book.pub_year);

    printf("Enter ISBN: ");
    scanf("%d", &book.isbn);

    printf("Enter price: ");
    scanf("%f", &book.price);

    book.available = 1;

    books[book_count++] = book;

    printf("\nBook added successfully!\n\n");
}

void display_book(Book book) {
    printf("Name: %s\n", book.name);
    printf("Author: %s\n", book.author);
    printf("Publisher: %s\n", book.publisher);
    printf("Publication Year: %d\n", book.pub_year);
    printf("ISBN: %d\n", book.isbn);
    printf("Price: %.2f\n", book.price);
    printf("Availability: %s\n", book.available ? "Available" : "Not Available");
}

void view_books() {
    if (book_count == 0) {
        printf("\nNo books found.\n\n");
        return;
    }

    printf("\nList of books:\n\n");

    for (int i = 0; i < book_count; i++) {
        printf("Book %d:\n", i + 1);
        display_book(books[i]);
        printf("\n");
    }
}

void delete_book() {
    int isbn;

    printf("Enter ISBN of book to be deleted: ");
    scanf("%d", &isbn);

    for (int i = 0; i < book_count; i++) {
        if (books[i].isbn == isbn) {
            for (int j = i; j < book_count - 1; j++) {
                books[j] = books[j + 1];
            }

            book_count--;

            printf("\nBook deleted successfully!\n\n");
            return;
        }
    }

    printf("\nBook not found.\n\n");
}

void borrow_book() {
    int isbn;
    char user_name[MAX_USER_NAME];

    printf("Enter ISBN of book to be borrowed: ");
    scanf("%d", &isbn);

    printf("Enter your name: ");
    scanf("%s", user_name);

    for (int i = 0; i < book_count; i++) {
        if (books[i].isbn == isbn) {
            if (books[i].available == 0) {
                printf("\nBook not available for borrowing.\n\n");
                return;
            }

            for (int j = 0; j < user_count; j++) {
                if (strcmp(users[j].name, user_name) == 0) {
                    if (users[j].borrowed_count == MAX_BOOKS) {
                        printf("\nYou have reached the maximum limit of borrowed books.\n\n");
                        return;
                    }

                    users[j].borrowed_books[users[j].borrowed_count++] = i;
                    books[i].available = 0;

                    printf("\nBook borrowed successfully!\n\n");
                    return;
                }
            }

            User user;
            strcpy(user.name, user_name);
            user.borrowed_books[user.borrowed_count++] = i;

            users[user_count++] = user;
            books[i].available = 0;

            printf("\nBook borrowed successfully!\n\n");
            return;
        }
    }

    printf("\nBook not found.\n\n");
}

void return_book() {
    int isbn;
    char user_name[MAX_USER_NAME];

    printf("Enter ISBN of book to be returned: ");
    scanf("%d", &isbn);

    printf("Enter your name: ");
    scanf("%s", user_name);

    for (int i = 0; i < book_count; i++) {
        if (books[i].isbn == isbn) {
            for (int j = 0; j < user_count; j++) {
                if (strcmp(users[j].name, user_name) == 0) {
                    for (int k = 0; k < users[j].borrowed_count; k++) {
                        if (users[j].borrowed_books[k] == i) {
                            users[j].borrowed_count--;

                            for (int l = k; l < users[j].borrowed_count; l++) {
                                users[j].borrowed_books[l] = users[j].borrowed_books[l + 1];
                            }

                            books[i].available = 1;

                            printf("\nBook returned successfully!\n\n");
                            return;
                        }
                    }

                    printf("\nYou have not borrowed this book.\n\n");
                    return;
                }
            }

            printf("\nUser not found.\n\n");
            return;
        }
    }

    printf("\nBook not found.\n\n");
}

void user_feedback() {
    char feedback[1000];

    printf("Enter your feedback: ");
    scanf("\n%[^\n]", feedback);

    FILE *fp = fopen("feedback.txt", "a");

    if (fp == NULL) {
        printf("Error: Unable to open file for writing.\n");
        return;
    }

    fprintf(fp, "%s\n", feedback);

    fclose(fp);

    printf("\nThank you for your feedback!\n\n");
}

int main() {
    int choice;

    while (1) {
        printf("1. Add book\n");
        printf("2. View books\n");
        printf("3. Delete book\n");
        printf("4. Borrow book\n");
        printf("5. Return book\n");
        printf("6. User feedback\n");
        printf("7. Exit\n");

        printf("\nEnter your choice: ");
        scanf("%d", &choice);

        switch (choice) {
            case 1:
                add_book();
                break;
            case 2:
                view_books();
                break;
            case 3:
                delete_book();
                break;
            case 4:
                borrow_book();
                break;
            case 5:
                return_book();
                break;
            case 6:
                user_feedback();
                break;
            case 7:
                exit(0);
            default:
                printf("\nInvalid choice. Please try again.\n\n");
                break;
        }
    }

    return 0;
}

以上是一个简单的图书借阅系统的代码实现，包括查看图书、添加图书、删除图书、借阅图书、归还图书、用户反馈等功能。需要注意的是，这只是一个简单的示例，实际应用中可能需要更多的功能和更复杂的实现。