Lesson 4: C# setup and .NET foundations: Refactoring strategy

Concept Explanation

"C# setup and .NET foundations: Refactoring strategy" is about taking a tiny piece of working code and reshaping it so the intent is easier to see. Instead of treating refactoring as a cosmetic pass, you will use it to make a small method easier to read, easier to test, and easier to extend later. The lesson stays beginner-friendly, but it also introduces a habit that matters in real .NET work: give simple logic clear names, keep each method focused, and make changes without breaking behavior.

Where to Put the Code

1. Define color and position variables at the top.
2. Create shape drawing or placement logic in the middle.
3. Render output (print, canvas, SVG, or styled block) at the end.

Command Reference

• Rename the method and parameters so the business meaning is obvious before you read the body.
• Run the original version, refactor it, and confirm the same input still produces the same result.
• Extract one tiny decision into a separate method only if it makes the code easier to scan.
• Write down one reason the refactored version would be easier to revisit next week.

Step-by-step Guide

1. Run the starter code once and note the expected result before changing anything.
2. Decide what the method is really responsible for and rename it to match that job.
3. Refactor one part of the code without changing the output for the sample input.
4. Test one normal case and one simple variation, such as a different quantity.
5. Finish with a quick check: are the names, method body, and output all easy to understand?

Practice Exercises

• Refactor a method that calculates a discount so the inputs and returned value are clearer.
• Rewrite the example using two small methods instead of one, but keep the behavior the same.
• Create a similar example for calculating a movie ticket total or grocery bill.

Coding Challenges

• Add input validation for negative values without turning the method into a long block of logic.
• Compare a compact one-line version with a more explicit version and explain which you would keep.

Mini Practice Tasks

• Rename one identifier to remove ambiguity.
• Add one extra test run with different numbers.
• Write a one-line note explaining what improved after refactoring.