C++ Loops Quiz - MCQ Questions and Answers

Welcome to our blog post, "C++ Loops Quiz - MCQ Questions and Answers." This quiz is specially designed for programmers and students who wish to strengthen their understanding of loops in C++, a fundamental concept in programming. Loops are essential for various tasks like iterating over arrays, processing data, and automating repetitive tasks. 

Our quiz comprises 20 multiple-choice questions that cover a range of topics from basic loop constructs to more advanced loop usage in C++. Whether you're revising for an exam, honing your coding skills, or just looking for a fun challenge, these questions will help solidify your knowledge of C++ loops. Get ready to test your skills and learn something new! Let's begin the journey.

1. What is the purpose of a loop in C++?

a) To perform a task once

b) To terminate the program

c) To repeat a block of code multiple times

d) To check the validity of data

Answer:

c) To repeat a block of code multiple times

Explanation:

Loops in C++ are used to execute a block of code repeatedly for a specified number of times or until a certain condition is met.

2. Which loop checks the condition before executing the loop body in C++?

a) do-while loop

b) while loop

c) for loop

d) infinite loop

Answer:

b) while loop

Explanation:

The while loop in C++ checks its condition before executing the loop body. If the condition is false initially, the loop body may not execute at all.

3. How do you write an infinite loop using the for statement in C++?

a) for(;;)

b) for(int i = 0; true; i++)

c) for(int i = 0; i < 10;)

d) Both a) and b)

Answer:

d) Both a) and b)

Explanation:

An infinite loop can be created using the for statement either by leaving all three components of the for loop empty (for(;;)) or by using a condition that always evaluates to true.

4. What is the use of the break statement in loops in C++?

a) To pause the loop

b) To stop the loop and exit it

c) To skip one iteration of the loop

d) To continue to the next iteration

Answer:

b) To stop the loop and exit it

Explanation:

The break statement is used within loops to immediately terminate the loop and transfer control to the statement following the loop.

5. Which loop executes its body at least once regardless of the condition in C++?

a) while loop

b) for loop

c) do-while loop

d) infinite loop

Answer:

c) do-while loop

Explanation:

The do-while loop in C++ executes its body at least once before checking the condition at the end of the loop.

6. How can you iterate over a range of values in C++11 and above?

a) Using a for loop

b) Using a while loop

c) Using a range-based for loop

d) Using a do-while loop

Answer:

c) Using a range-based for loop

Explanation:

In C++11 and later, a range-based for loop can be used to iterate over a range of values, such as elements in an array or a container.

7. What is the correct syntax for a for loop in C++?

a) for(initialization; condition; increment/decrement) { /* code */ }

b) for(condition; initialization; increment/decrement) { /* code */ }

c) for(initialization; increment/decrement; condition) { /* code */ }

d) for(increment/decrement; initialization; condition) { /* code */ }

Answer:

a) for(initialization; condition; increment/decrement) { /* code */ }

Explanation:

The correct syntax for a for loop in C++ includes initialization first, followed by the condition, and then the increment or decrement operation.

8. What does the continue statement do in a loop in C++?

a) Terminates the loop

b) Skips the rest of the loop body and proceeds with the next iteration

c) Pauses the execution of the loop

d) Continues execution without checking the condition

Answer:

b) Skips the rest of the loop body and proceeds with the next iteration

Explanation:

The continue statement in a loop causes the loop to skip the remainder of its body and proceed with the next iteration of the loop.

9. What is the output of the following C++ code?

   for(int i = 0; i < 5; i++) {
       if(i == 2) continue;
       cout << i << " ";
   }

a) 0 1 2 3 4

b) 0 1 3 4

c) 1 2 3 4 5

d) 0 1 2 3

Answer:

b) 0 1 3 4

Explanation:

The loop iterates from 0 to 4, but when i is equal to 2, the continue statement is executed, which skips the current iteration, so 2 is not printed.

10. Which of the following is not a loop structure in C++?

a) while

b) for

c) do-while

d) repeat-until

Answer:

d) repeat-until

Explanation:

repeat-until is not a loop structure in C++. The loop structures in C++ are while, for, and do-while.

11. How do you exit a loop in C++ based on a condition inside the loop body?

a) Using the exit() function

b) Using the break statement

c) Using the return statement

d) By setting the loop condition to false

Answer:

b) Using the break statement

Explanation:

To exit a loop based on a condition inside the loop body, the break statement is used. It immediately terminates the loop execution.

12. What is a nested loop in C++?

a) A loop inside another loop

b) Looping over nested data structures

c) A loop that executes infinitely

d) A loop that contains a switch statement

Answer:

a) A loop inside another loop

Explanation:

A nested loop in C++ is a loop that is placed inside the body of another loop, allowing you to perform more complex tasks like working with multidimensional arrays.

13. What is the initial value of a loop counter in a standard for loop in C++?

a) 0

b) 1

c) The value specified in the initialization statement

d) Undefined

Answer:

c) The value specified in the initialization statement

Explanation:

The initial value of a loop counter in a for loop is the value assigned to it in the initialization statement of the loop.

14. How do you create an infinite loop using the while statement in C++?

a) while(true) { /* code */ }

b) while(1) { /* code */ }

c) while(false) { /* code */ }

d) Both a) and b)

Answer:

d) Both a) and b)

Explanation:

An infinite loop using the while statement can be created either by setting the condition to true (while(true)) or using a non-zero value like 1 (while(1)).

15. What is the role of the semicolon in a for loop statement in C++?

a) To terminate the loop

b) To separate the initialization, condition, and increment/decrement expressions

c) To indicate the end of the loop body

d) To separate statements inside the loop body

Answer:

b) To separate the initialization, condition, and increment/decrement expressions

Explanation:

In a for loop, semicolons are used to separate the initialization expression, loop condition, and increment or decrement expression.

16. What happens if the condition in a while loop is always true in C++?

a) The loop executes once

b) The loop becomes a for loop

c) The loop executes indefinitely (infinite loop)

d) The loop is skipped

Answer:

c) The loop executes indefinitely (infinite loop)

Explanation:

If the condition in a while loop is always true, it results in an infinite loop, where the loop body executes indefinitely until externally stopped or interrupted.

17. Can the loop control variables be declared inside the for loop in C++?

a) Yes, always

b) No, never

c) Only in C++11 and later

d) Only for integer types

Answer:

c) Only in C++11 and later

Explanation:

Starting with C++11, loop control variables can be declared inside the for loop itself, limiting their scope to the loop.

18. How do you ensure a loop executes a specific number of times in C++?

a) By using a while loop with a counter

b) By using a for loop with a fixed count

c) By using a do-while loop with a counter

d) All of the above

Answer:

d) All of the above

Explanation:

To ensure a loop executes a specific number of times, you can use a while, for, or do-while loop with a counter or a condition that ensures the desired number of iterations.

19. What is the output of the following C++ code?

int i = 0;
   do {
       cout << i << " ";
       i++;
   } while(i < 3);

a) 0 1 2

b) 0 1 2 3

c) 1 2 3

d) 0 1

Answer:

a) 0 1 2

Explanation:

The do-while loop executes the loop body first and then checks the condition. In this case, it prints 0, 1, and 2 before the condition i < 3 becomes false.

20. What is the purpose of the scope resolution operator '::' in loop statements in C++?

a) To define the scope of the loop variable

b) To access a global variable that has the same name as a loop variable

c) To terminate the loop

d) It is not used in loop statements

Answer:

b) To access a global variable that has the same name as a loop variable

Explanation:

The scope resolution operator '::' is used to access a global variable when there is a local variable with the same name, but it is not specifically used for or related to loop statements.