What is a switch statement in C#?

A switch statement executes one of many code blocks depending on the value of an expression.

How does switch differ from if-else in C#?

Switch improves readability when checking one value against many cases, whereas if-else can handle complex conditions.

How Does the Switch Statement Work in C# | FullStackPrep.Dev

💡 Concept: Switch Statement in C#

The switch statement in C# is used for decision-making. It evaluates an expression and executes the matching case block based on the result, improving readability over multiple if-else conditions.

📘 Quick Intro

switch is a control flow statement that selects a code block to execute based on the value of an expression. It supports patterns and multiple case labels, and in modern C#, supports enhanced match expressions.

🧠 Analogy

Think of a vending machine. You press a button (input), and it delivers a specific item (case block). The machine doesn’t check all items—just the one mapped to your input. That’s how switch optimizes flow.

🔧 Technical Explanation

Works with types like int, char, string, enum, and patterns (C# 7+).
Each case must end with break, return, or control flow redirection.
default handles unmatched cases.
Pattern matching and when clauses enable more powerful use in modern C#.
Fall-through behavior is not allowed unless using pattern matching or goto case.

🎯 Use Cases

Menu selection or command execution.
Mapping enums to user-readable output.
Routing logic in desktop or web applications.
Reducing complexity in nested if-else chains.

💻 Real Code Example

int day = 3;
switch (day)
{
    case 1:
        Console.WriteLine("Monday");
        break;
    case 2:
        Console.WriteLine("Tuesday");
        break;
    case 3:
        Console.WriteLine("Wednesday");
        break;
    default:
        Console.WriteLine("Unknown day");
        break;
}

❓ Interview Q&A

Q1: What is a switch statement?
A: A control flow tool that executes one block of code based on a value match.

Q2: When is switch preferred over if-else?
A: When checking one variable against multiple constant values.

Q3: Can switch work with strings?
A: Yes, since C# 7.0.

Q4: What happens if no case matches?
A: The default block runs, if defined.

Q5: Is fall-through allowed like in C or Java?
A: No, each case must end with break or similar.

Q6: Can multiple cases map to the same block?
A: Yes, by grouping them without a break.

Q7: What is pattern matching in switch?
A: Matching based on type and condition using is and when.

Q8: Can switch be used inside a method return?
A: Yes, especially in expression-bodied members (C# 8+).

Q9: What’s the purpose of the goto case?
A: It transfers control to another case label.

Q10: Can switch handle ranges?
A: Yes, using relational patterns in newer C# versions.

📝 MCQs

Q1. Which types are supported in switch?

Only int
Only string
All objects
int, char, string, enum

Q2. What must each case end with?

continue
stop
break or return
pause

Q3. What is the purpose of default case?

Start first
Handle unmatched values
Compile faster
Ignore input

Q4. Can switch handle strings?

No
Only in Java
Yes
Only with enum

Q5. What happens without a break?

Fall-through
No output
Skip case
Compiler error

Q6. Is switch more efficient than if-else?

Always
Never
Sometimes
Only with enums

Q7. What does goto case do?

Restarts
Ends switch
Jumps to another case
None

Q8. When is switch preferred?

Nested loops
One condition
Multiple conditions on one variable
Class inheritance

Q9. Can switch use pattern matching?

No
Only Java
Yes, in modern C#
Only for arrays

Q10. What is printed if no match and no default?

Error
Null
Default value
Nothing

💡 Bonus Insight

In modern C#, switch expressions allow more expressive logic using pattern matching, simplifying complex conditionals. They're ideal for compact returns in LINQ or APIs.

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How Does the Switch Statement Work in C#?