MCQs on Control Flow Statements | C#

Understanding control flow statements like conditional statements, loops, break/continue, and exception handling is essential for writing clean and efficient C# code. This guide will walk you through each concept.

Control Flow Statements in C# – 30 Multiple Choice Questions

1. Conditional Statements (if, if-else, switch)

1. Which of the following is a valid syntax for the if statement in C#?
   • A) if(condition) { //code }
   • B) if { condition; }
   • C) if (condition) { code } else
   • D) if: condition { code }
2. What will be the output of the following C# code?csharpCopy codeint x = 5; if (x > 3) { Console.WriteLine("Greater"); } else { Console.WriteLine("Smaller"); }
   • A) Greater
   • B) Smaller
   • C) Error
   • D) Nothing
3. Which of the following is the correct way to use an if-else statement in C#?
   • A) if (condition) { //block } else { //block }
   • B) if condition { //block } else { }
   • C) if (condition) { } else
   • D) else { } if (condition) { }
4. What does the switch statement do in C#?
   • A) Executes one block of code out of multiple choices based on an expression
   • B) Loops through all possible cases
   • C) Breaks out of the loop when the condition is met
   • D) Compares two values for equality
5. In a switch statement, if no case matches, which statement is executed?
   • A) Default
   • B) Else
   • C) Continue
   • D) Break
6. What is the correct syntax to define a case in a switch statement in C#?
   • A) case value: { //code }
   • B) case value; { //code }
   • C) case value() { //code }
   • D) switch(value) { //cases }
7. Which statement is used to exit a switch block early in C#?
   • A) Return
   • B) Continue
   • C) Break
   • D) Exit
8. In C#, how many else statements can you use in an if-else block?
   • A) Only one
   • B) As many as needed
   • C) Zero
   • D) None
9. What is the purpose of the default keyword in a switch statement?
   • A) To handle unexpected input or cases
   • B) To loop through all cases
   • C) To break out of the switch block
   • D) To compare values
10. Which of the following will cause an error in a C# switch statement?
    • A) Using break in a case block
    • B) Using if inside a case block
    • C) Omitting a default case
    • D) Using a non-constant value in a case

2. Looping Statements (for, while, do-while, foreach)

11. Which loop is guaranteed to run at least once in C#?
    • A) for
    • B) while
    • C) do-while
    • D) foreach
12. Which of the following loops can iterate over a collection in C#?
    • A) for
    • B) foreach
    • C) while
    • D) do-while
13. What is the syntax for a for loop in C#?
    • A) for (initialization; condition; increment) { }
    • B) for (initialization) { condition } { increment }
    • C) for (condition) { initialization; increment; }
    • D) for { initialization; condition; increment }
14. How does a while loop in C# work?
    • A) It runs as long as the condition evaluates to true
    • B) It runs until the condition is false
    • C) It executes a fixed number of times
    • D) It runs indefinitely
15. Which of the following describes the behavior of a do-while loop in C#?
    • A) The condition is evaluated before the loop runs
    • B) The loop runs at least once regardless of the condition
    • C) The loop runs as long as the condition is false
    • D) It executes only if the condition is true initially
16. What will the following for loop do?csharpCopy codefor (int i = 0; i < 5; i++) { Console.WriteLine(i); }
    • A) Print numbers from 0 to 5
    • B) Print numbers from 1 to 5
    • C) Print numbers from 0 to 4
    • D) Print 5 only
17. What is the purpose of the foreach loop in C#?
    • A) It is used to loop through arrays or collections
    • B) It is used to execute a block of code a fixed number of times
    • C) It is used to loop while a condition is true
    • D) It loops through elements based on index
18. Which of the following is NOT a valid loop type in C#?
    • A) for
    • B) foreach
    • C) repeat
    • D) while
19. How do you exit a loop early in C#?
    • A) exit
    • B) stop
    • C) return
    • D) break
20. What will be the output of the following code?csharpCopy codeint x = 0; while (x < 3) { Console.WriteLine(x); x++; }
    • A) 0, 1, 2, 3
    • B) 0, 1, 2
    • C) 1, 2, 3
    • D) 0, 1

3. Break and Continue Statements

21. What is the function of the break statement in C#?
    • A) Exits the loop or switch statement immediately
    • B) Skips the current iteration and continues to the next one
    • C) Ends the program
    • D) Pauses the loop until a condition is met
22. Which of the following statements is used to skip the rest of the current loop iteration in C#?
    • A) exit
    • B) continue
    • C) pause
    • D) return
23. Can the break statement be used in a switch statement in C#?
    • A) Yes, to exit the switch case
    • B) No, the return statement must be used
    • C) Yes, to skip the current case
    • D) No, break is not allowed in switch statements
24. What happens if a continue statement is encountered in a for loop?
    • A) The loop stops and the program exits
    • B) The loop skips the current iteration and continues with the next one
    • C) The loop terminates
    • D) The loop runs indefinitely
25. How do break and continue differ in their functionality in C#?
    • A) break exits the loop, while continue skips the current iteration
    • B) break skips the iteration, while continue exits the loop
    • C) Both have the same effect
    • D) break exits the program, while continue skips the loop
26. Which of the following can the break statement be used in?
    • A) Loops only
    • B) Switch statements only
    • C) Loops and switch statements
    • D) Functions
27. Which of the following will prevent an infinite loop in C#?
    • A) continue inside the loop
    • B) Using break after a certain number of iterations
    • C) Using return inside the loop
    • D) Both B and C
28. What will the following code do?csharpCopy codefor (int i = 0; i < 5; i++) { if (i == 3) break; Console.WriteLine(i); }
    • A) Prints 0, 1, 2, 3
    • B) Prints 0, 1, 2
    • C) Prints 0, 1, 2, 3, 4
    • D) Prints 3
29. How do you skip even numbers in a loop using continue?
    • A) Use continue if the number is even
    • B) Use continue if the number is odd
    • C) Use break for even numbers
    • D) Use continue for odd numbers
30. In which scenario would you most likely use a break statement in a loop?
    • A) When you want to skip an iteration of the loop
    • B) When you want to exit the loop after a certain condition is met
    • C) To pause the loop at a certain point
    • D) To restart the loop

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