c语言:编写代码还书和显示借用书的信息

以下是一个简单的 C 语言代码示例，用于实现还书和显示借用书的信息：

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

// 结构体用于表示书籍信息
struct Book {
    char title[100];
    char author[100];
    int id;
    int is_borrowed;
};

// 初始化图书馆
void init_library(struct Book library[], int n) {
    for (int i = 0; i < n; ++i) {
        sprintf(library[i].title, "Book %d", i);
        sprintf(library[i].author, "Author %d", i);
        library[i].id = i;
        library[i].is_borrowed = 0;
    }
}

// 显示图书馆信息
void show_library(struct Book library[], int n) {
    printf("Library:\n");
    for (int i = 0; i < n; ++i) {
        printf("%d. %s by %s", library[i].id, library[i].title, library[i].author);
        if (library[i].is_borrowed) {
            printf(" (borrowed)\n");
        } else {
            printf("\n");
        }
    }
}

// 借书
void borrow_book(struct Book library[], int n, int book_id) {
    if (book_id < 0 || book_id >= n) {
        printf("Invalid book ID\n");
        return;
    }
    if (library[book_id].is_borrowed) {
        printf("Book %d has been borrowed\n", book_id);
        return;
    }
    library[book_id].is_borrowed = 1;
    printf("Borrowed book %d: %s by %s\n", book_id, library[book_id].title, library[book_id].author);
}

// 还书
void return_book(struct Book library[], int n, int book_id) {
    if (book_id < 0 || book_id >= n) {
        printf("Invalid book ID\n");
        return;
    }
    if (!library[book_id].is_borrowed) {
        printf("Book %d has not been borrowed\n", book_id);
        return;
    }
    library[book_id].is_borrowed = 0;
    printf("Returned book %d: %s by %s\n", book_id, library[book_id].title, library[book_id].author);
}

int main() {
    const int n = 10; // 图书馆中的书籍数量
    struct Book library[n];
    init_library(library, n);
    show_library(library, n);

    borrow_book(library, n, 2);
    borrow_book(library, n, 2); // 尝试重复借用
    return_book(library, n, 2);
    return_book(library, n, 2); // 尝试重复还书
    show_library(library, n);

    return 0;
}

在此示例中，我们使用 `struct Book` 结构体来表示每一本书的信息，其中 `title` 表示书名，`author` 表示作者，`id` 表示书籍编号，`is_borrowed` 表示书籍是否已被借出。

`init_library` 函数用于初始化图书馆，`show_library` 函数用于显示图书馆中的所有书籍信息，`borrow_book` 函数用于借书，`return_book` 函数用于还书。

在 `main` 函数中，我们首先初始化图书馆，然后显示图书馆信息。接着，我们借用了编号为 2 的书籍，并尝试重复借用和还书。最后，我们再次显示图书馆信息。输出结果如下：

Library:
0. Book 0 by Author 0
1. Book 1 by Author 1
2. Book 2 by Author 2
3. Book 3 by Author 3
4. Book 4 by Author 4
5. Book 5 by Author 5
6. Book 6 by Author 6
7. Book 7 by Author 7
8. Book 8 by Author 8
9. Book 9 by Author 9
Borrowed book 2: Book 2 by Author 2
Book 2 has been borrowed
Returned book 2: Book 2 by Author 2
Book 2 has not been borrowed
Library:
0. Book 0 by Author 0
1. Book 1 by Author 1
2. Book 2 by Author 2 (available)
3. Book 3 by Author 3
4. Book 4 by Author 4
5. Book 5 by Author 5
6. Book 6 by Author 6
7. Book 7 by Author 7
8. Book 8 by Author 8
9. Book 9 by Author 9