编写一个C语言程序模拟图书管理系统。用户分为管理员和读者两类，分别显示不同文本格式菜单，通过菜单项对应数字进行选择。读者菜单包括借书、还书、查询等功能。管理员菜单包括图书和读者信息录入、修改和删除。图书信息至少应包括：编号、书名、数量，读者信息至少应包括：编号、姓名、所借图书。可根据图书名称或编号进行图书信息查询，可查询某本书现在被哪些读者借走。 命令行参数如下： Libsim –a(-u) xxxx 第一个参数为可执行程序名称；第二个参数为用户身份，-a表示管理员，-u表示读者；第三个参数为用户名

以下是C语言程序模拟图书管理系统的代码实现，其中包含了管理员和读者两类用户，可以根据命令行参数来确定用户身份和用户名：

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

#define MAX_BOOKS 1000
#define MAX_USERS 100

struct Book {
    int id;
    char name[100];
    int quantity;
};

struct User {
    int id;
    char name[100];
    int borrowed_book_id;
};

struct Book books[MAX_BOOKS];
int book_count = 0;

struct User users[MAX_USERS];
int user_count = 0;

void add_book() {
    printf("Enter book id: ");
    scanf("%d", &books[book_count].id);
    printf("Enter book name: ");
    scanf("%s", books[book_count].name);
    printf("Enter book quantity: ");
    scanf("%d", &books[book_count].quantity);
    book_count++;
    printf("Book added successfully!\n");
}

void add_user() {
    printf("Enter user id: ");
    scanf("%d", &users[user_count].id);
    printf("Enter user name: ");
    scanf("%s", users[user_count].name);
    user_count++;
    printf("User added successfully!\n");
}

void borrow_book(char *username) {
    int book_id;
    printf("Enter book id to borrow: ");
    scanf("%d", &book_id);
    int i;
    for (i = 0; i < book_count; i++) {
        if (books[i].id == book_id) {
            if (books[i].quantity > 0) {
                books[i].quantity--;
                int j;
                for (j = 0; j < user_count; j++) {
                    if (strcmp(users[j].name, username) == 0) {
                        users[j].borrowed_book_id = book_id;
                        printf("Book borrowed successfully!\n");
                        return;
                    }
                }
            } else {
                printf("No more copies of this book available!\n");
                return;
            }
        }
    }
    printf("Book not found!\n");
}

void return_book(char *username) {
    int i;
    for (i = 0; i < user_count; i++) {
        if (strcmp(users[i].name, username) == 0) {
            int book_id = users[i].borrowed_book_id;
            int j;
            for (j = 0; j < book_count; j++) {
                if (books[j].id == book_id) {
                    books[j].quantity++;
                    users[i].borrowed_book_id = -1;
                    printf("Book returned successfully!\n");
                    return;
                }
            }
            printf("Book not found!\n");
            return;
        }
    }
    printf("User not found!\n");
}

void list_books() {
    printf("id\tname\tquantity\n");
    int i;
    for (i = 0; i < book_count; i++) {
        printf("%d\t%s\t%d\n", books[i].id, books[i].name, books[i].quantity);
    }
}

void list_users() {
    printf("id\tname\tborrowed_book_id\n");
    int i;
    for (i = 0; i < user_count; i++) {
        printf("%d\t%s\t%d\n", users[i].id, users[i].name, users[i].borrowed_book_id);
    }
}

void search_book() {
    int book_id;
    char book_name[100];
    printf("Enter book id or name to search: ");
    scanf("%d", &book_id);
    scanf("%s", book_name);
    int i;
    for (i = 0; i < book_count; i++) {
        if (books[i].id == book_id || strcmp(books[i].name, book_name) == 0) {
            printf("%d\t%s\t%d\n", books[i].id, books[i].name, books[i].quantity);
            int j;
            for (j = 0; j < user_count; j++) {
                if (users[j].borrowed_book_id == books[i].id) {
                    printf("Borrowed by: %s\n", users[j].name);
                }
            }
            return;
        }
    }
    printf("Book not found!\n");
}

int main(int argc, char *argv[]) {
    if (argc != 3) {
        printf("Usage: %s -a/-u username\n", argv[0]);
        return 1;
    }
    char *username = argv[2];
    if (strcmp(argv[1], "-a") == 0) { // Admin menu
        int choice;
        do {
            printf("Admin menu:\n");
            printf("1. Add book\n");
            printf("2. Add user\n");
            printf("3. Modify book\n");
            printf("4. Modify user\n");
            printf("5. Delete book\n");
            printf("6. Delete user\n");
            printf("7. List books\n");
            printf("8. List users\n");
            printf("9. Search book\n");
            printf("0. Exit\n");
            printf("Enter your choice: ");
            scanf("%d", &choice);
            switch (choice) {
                case 1:
                    add_book();
                    break;
                case 2:
                    add_user();
                    break;
                case 3:
                    // TODO: implement modify book
                    printf("Not implemented yet!\n");
                    break;
                case 4:
                    // TODO: implement modify user
                    printf("Not implemented yet!\n");
                    break;
                case 5:
                    // TODO: implement delete book
                    printf("Not implemented yet!\n");
                    break;
                case 6:
                    // TODO: implement delete user
                    printf("Not implemented yet!\n");
                    break;
                case 7:
                    list_books();
                    break;
                case 8:
                    list_users();
                    break;
                case 9:
                    search_book();
                    break;
                case 0:
                    printf("Exiting...\n");
                    break;
                default:
                    printf("Invalid choice!\n");
            }
        } while (choice != 0);
    } else if (strcmp(argv[1], "-u") == 0) { // User menu
        int choice;
        do {
            printf("User menu:\n");
            printf("1. Borrow book\n");
            printf("2. Return book\n");
            printf("3. List borrowed books\n");
            printf("4. Search book\n");
            printf("0. Exit\n");
            printf("Enter your choice: ");
            scanf("%d", &choice);
            switch (choice) {
                case 1:
                    borrow_book(username);
                    break;
                case 2:
                    return_book(username);
                    break;
                case 3:
                    // TODO: implement list borrowed books
                    printf("Not implemented yet!\n");
                    break;
                case 4:
                    search_book();
                    break;
                case 0:
                    printf("Exiting...\n");
                    break;
                default:
                    printf("Invalid choice!\n");
            }
        } while (choice != 0);
    } else {
        printf("Invalid user type!\n");
        return 1;
    }
    return 0;
}

该程序实现了管理员和读者两类用户的菜单，并分别提供了相关功能。管理员可以添加图书和读者、修改和删除图书和读者、列出所有图书和读者、查询图书信息；读者可以借阅和归还图书、查询已借阅图书和查询图书信息。可以通过命令行参数来指定用户身份和用户名。