图书管理系统流程图代码

图书管理系统流程图通常会展示从用户借阅、归还图书，到管理员添加、更新图书，以及查询和统计等功能的操作步骤。以下是一个简化版的图书管理系统流程图代码示例，使用的是流程图语言（如UML或活动图）：

sequenceDiagram
    participant User
    participant Librarian
    participant System

    User->>System: Login
    alt Successful Login
        System->>User: Welcome, show Catalog
        User->>System: Search Book
        System->>Librarian: Request Book Info
        Librarian->>System: Provide Book Info
        System->>User: Display Book Details
        User->>System: Borrow Book
        System->>Librarian: Update Borrow Record
    else Failed Login
        System->>User: Incorrect credentials, try again
    end

    alt Book Returned
        User->>System: Return Book
        System->>Librarian: Update Return Record
    else Extend Loan
        User->>System: Request Book Extension
        Librarian->>System: Approve/Reject Extension
        System->>User: Notify Result
    end

    Librarian->>System: Add/Update Books
    Librarian->>System: Manage Inventory
    System->>Librarian: Generate Reports
    System->>User: Logout