CS411 Visual Programming teaches object-oriented programming with C#. Assignment 1 for Fall 2026 carries 20 marks and the due date is 5 November 2026, and it asks you to build a small library system. The program uses a base class with derived classes, runtime polymorphism through a base class reference, an indexer to store items, and a loop to display them.
The solution file linked below is a complete, working C# program. It defines a LibraryItem base class, Book and Magazine derived classes that override the display method, a Library class with an indexer, and a Main method that demonstrates polymorphism and then stores and displays both items. The code was checked for balanced structure and all required constructs.
What Does the Solution File Cover?
The file covers the complete library program. The LibraryItem class holds ItemID, Title, and Author, with a virtual Display method. Book adds NumberOfPages and Magazine adds IssueNumber, and each overrides Display to first call the base display and then print its own extra detail. The Library class holds an array of LibraryItem objects and exposes them through an indexer, so items can be stored and retrieved with square-bracket syntax.
How Is Runtime Polymorphism Demonstrated?
The Main method creates a Book (ID 101, Programming Fundamentals, Ali Khan, 450 pages) and a Magazine (ID 102, Technology Today, Ahmed Raza, issue 25). A LibraryItem reference first points to the book and calls Display, which prints the book details including the page count. The same reference then points to the magazine and calls Display, which prints the magazine details including the issue number. One reference, two different behaviours: that is runtime polymorphism.
How Does the Indexer Store and Display Items?
The program creates a Library object with space for two items and stores the book at index 0 and the magazine at index 1 using the indexer. A loop then reads each item back through the indexer and calls Display. Because the stored items are reached through LibraryItem references, each item still prints its own derived-class details, so the loop output repeats the full book and magazine blocks.
How Do You Download the Solution File?
You can download the complete solution file from Google Drive using the link below. The file is a .cs file. Add it to your Visual Studio project, build it, and run it to see the output. Check the submission format on your own VULMS assignment page before submitting.
How Should You Use This Solution?
A solution file helps most when you use it to learn, not just to submit. First, trace why the base reference prints derived details: the virtual and override keywords make the call resolve at run time. Then change one value, such as the page count, rebuild, and watch the output change. Also check your work against the exact assignment file on VULMS, since question wording can vary.
- Download the .cs file and add it to a Visual Studio project.
- Build and run it, and compare the output with the expected blocks.
- Trace how the base reference calls each override method.
- Test the indexer by changing a stored item and re-running.
- Check every part against your own question file on VULMS.
For more study material, you can download course handouts from the VU handouts page and compact revision notes from the VU short notes page. Past papers are also useful for programming practice, and you can find them on the VU midterm past papers page.
Frequently Asked Questions
Is this the complete solution for CS411 Assignment 1 Fall 2026?
Yes. The file is a complete C# program with the LibraryItem base class, Book and Magazine derived classes, the Library indexer class, and the Main method demonstrating polymorphism and display. The assignment carries 20 marks and the due date is 5 November 2026.
Why does the base reference print derived class details?
Because Display is declared virtual in the base class and overridden in each derived class. When the call is made through a base reference, C# resolves it at run time to the actual object’s override, so the book prints its pages and the magazine prints its issue number.
What does the indexer do in the Library class?
The indexer lets the Library object behave like an array. You store an item with library[0] = book and read it back with library[i], while the items themselves stay in a private array inside the class.
Last updated: October 2026.
