Switch Case — Routing the Blueprint 15 XP Easy

🔀 The Material Routing Station

Welcome back, Architect! Your digital city is growing fast, and construction materials are flooding in — steel beams, concrete blocks, glass panels, timber planks. Each material needs to be routed to the correct department for inspection.

You could use a long chain of if/else if statements… but there's an elegant alternative: the switch statement. Think of it as a sorting machine — you feed it a value, and it finds the matching chute to send it down.

📦 The Classic Switch Statement

The traditional switch compares a single value against multiple case labels:

🔑 Key Rules of switch

• break is required at the end of each case in C#. Unlike C/C++, C# does NOT allow implicit fall-through between cases that contain code.
• default handles any value that doesn't match a case — like the "miscellaneous" bin. It's optional but highly recommended.
• You CAN stack multiple cases together (explicit fall-through) when they share the same logic:
• The switch value can be: string, int, char, enum, bool, or any type that supports ==.

🪜 Stacking Cases (Shared Logic)

Sometimes two materials go to the same department. You can stack cases with no code between them:

✨ Switch Expressions (C# 8+) — The Modern Way

C# 8 introduced switch expressions — a cleaner, more concise syntax that returns a value. This is the modern architect's preferred tool:

⚡ Switch Expression vs Switch Statement

• Switch statement: Executes code blocks. Uses case/break. Good for complex multi-line logic.
• Switch expression: Returns a value. Uses => (lambda arrows). Terser. Ideal for mapping one value to another.
• The _ in switch expressions is the discard pattern — it matches anything (like default).
• Switch expressions throw a SwitchExpressionException if no arm matches and there's no discard _.

🔢 Switching on Integers and Enums

Switch works beautifully with numeric types and enums:

⚠️ Why No Fall-Through in C#?

In C and C++, forgetting break causes "fall-through" — execution silently continues into the next case. This is a legendary source of bugs. C# designers said "never again" and made break mandatory for non-empty cases. Smart architects learn from the mistakes of the past!

🏗️ Your Mission

The material routing station needs a controller program. Given a material name, route it to the correct department and assign a priority level. The city depends on your sorting skills!