1. What is the basic structure of a while loop in C#?
a) while (condition) { /* code */ }
b) while condition { /* code */ }
c) while (condition) -> { /* code */ }
d) while: (condition) { /* code */ }
Answer:
a) while (condition) { /* code */ }
Explanation:
The while loop in C# starts with the 'while' keyword followed by a condition in parentheses and a block of code in curly braces.
2. How many times does the code inside a while loop execute if the condition is initially false?
a) Once
b) Twice
c) Zero times
d) Infinite times
Answer:
c) Zero times
Explanation:
If the condition of a while loop is false initially, the loop's code block will not execute at all.
3. Which of the following is essential to prevent a while loop from running indefinitely?
a) A break statement
b) An increment or decrement operation within the loop
c) A return statement
d) An else statement
Answer:
b) An increment or decrement operation within the loop
Explanation:
To prevent an infinite loop, the condition of the while loop must eventually become false, often achieved by modifying a variable within the loop.
4. What is an infinite loop in C#?
a) A loop that runs a fixed number of times
b) A loop that never starts
c) A loop that doesn't have a body
d) A loop that runs indefinitely
Answer:
d) A loop that runs indefinitely
Explanation:
An infinite loop is a loop where the condition never becomes false, causing it to run indefinitely.
5. What will be the output of the following code?
int i = 1;
while (i <= 3)
{
Console.WriteLine(i);
i++;
}
a) 1 2 3
b) 1 2
c) 1 2 3 4
d) The loop does not execute
Answer:
a) 1 2 3
Explanation:
The while loop prints the numbers 1, 2, and 3 as it increments 'i' each time until 'i' is greater than 3.
6. Is it possible to exit a while loop without meeting the condition in C#?
a) Yes, using the break statement
b) No, the condition must be met
c) Yes, using the continue statement
d) No, while loops cannot be exited prematurely
Answer:
a) Yes, using the break statement
Explanation:
The break statement can be used to exit a while loop immediately, regardless of the loop's condition.
7. What happens if the increment statement in a while loop is accidentally omitted?
a) The loop will execute once
b) The loop will terminate immediately
c) The loop may become an infinite loop
d) A compile-time error will occur
Answer:
c) The loop may become an infinite loop
Explanation:
If the increment (or decrement) statement is omitted, the condition of the loop may never become false, leading to an infinite loop.
8. Which of the following statements is true about the while loop in C#?
a) The while loop is a pre-test loop
b) The while loop is a post-test loop
c) The condition in a while loop can only be a boolean variable
d) The while loop cannot be used for iteration
Answer:
a) The while loop is a pre-test loop
Explanation:
In a while loop, the condition is tested before the execution of the loop's body, making it a pre-test loop.
9. How can you skip the current iteration in a while loop in C#?
a) Using the break statement
b) Using the continue statement
c) Using the pass statement
d) Using the skip statement
Answer:
b) Using the continue statement
Explanation:
The continue statement is used to skip the remaining code in the current iteration and proceeds to the next iteration of the loop.
10. Which of the following is a valid while loop in C#?
a) while true { /* code */ }
b) while (true) { /* code */ }
c) while (true) -> { /* code */ }
d) while: (true) { /* code */ }
Answer:
b) while (true) { /* code */ }
Explanation:
The correct syntax for a while loop includes the condition in parentheses.
11. What is the role of the condition in a while loop?
a) It determines how many times the loop will run
b) It determines whether the loop's code block will execute
c) It increments a counter variable
d) It is optional and can be omitted
Answer:
b) It determines whether the loop's code block will execute
Explanation:
The condition in a while loop determines whether or not the loop's code block should be executed.
12. Can a while loop contain multiple conditions in C#?
a) Yes, separated by commas
b) Yes, using logical operators like && and ||
c) No, it can only have a single condition
d) Yes, but only using bitwise operators
Answer:
b) Yes, using logical operators like && and ||
Explanation:
Multiple conditions in a while loop can be combined using logical operators such as && (and) and || (or).
13. What happens when a return statement is executed inside a while loop?
a) The loop pauses and resumes after the function call
b) The loop continues to the next iteration
c) The function containing the loop returns immediately
d) The loop exits and the rest of the function continues
Answer:
c) The function containing the loop returns immediately
Explanation:
When a return statement is executed inside a while loop, the function containing the loop returns immediately, exiting the loop.
14. In C#, what is the difference between a while loop and a do-while loop?
a) A while loop is a pre-test loop, and a do-while loop is a post-test loop
b) There is no difference; they function identically
c) A do-while loop cannot have a break statement
d) A while loop cannot be nested, but a do-while loop can
Answer:
a) A while loop is a pre-test loop, and a do-while loop is a post-test loop
Explanation:
The main difference is that a while loop checks its condition before the first iteration (pre-test), whereas a do-while loop checks its condition after the first iteration (post-test).
15. How can you ensure a while loop executes at least once in C#?
a) By setting the initial condition to true
b) By using a do-while loop instead
c) By placing the condition at the end of the loop
d) By initializing all variables outside the loop
Answer:
b) By using a do-while loop instead
Explanation:
To ensure a loop executes at least once regardless of the condition, a do-while loop should be used, as it checks the condition after executing the loop's body.