JavaScript Control Flow: Master the Flow of Your Code

Question 1

Which of these is NOT a JavaScript control flow statement?

Accepted Answer

goto

Answer

if

Answer

for

Question 2

Which key advantage does a switch statement offer over multiple if-else statements in JavaScript?

Accepted Answer

Improved code clarity and ease of maintenance

Answer

Boosted program speed

Answer

Reduced memory usage

Answer

Enhanced flexibility for handling complex conditions

Question 3

To iterate through an array with a known length, which loop type is most suitable?

Accepted Answer

For loop

Answer

While loop

Answer

Do-while loop

Question 4

In a 'while' loop, what does the 'continue' statement do?

Accepted Answer

Skips the rest of the current iteration and moves to the next one.

Answer

Ends the loop and moves to the code after the loop.

Answer

Exits the loop and moves to the code after the loop.

Question 5

What is the correct syntax for an if statement in JavaScript?

Accepted Answer

if (condition) { code_to_execute }

Answer

if (condition) code_to_execute;

Answer

if condition { code_to_execute }

Answer

while (condition) { code_to_execute }

Question 6

Which statement is used to execute a block of code if a specified condition is met?

Accepted Answer

if statement

Answer

switch statement

Answer

loop statement

Question 7

Which loop will continue executing as long as a specified condition remains true?

Accepted Answer

while loop

Answer

switch statement

Answer

for loop

Answer

if statement

Question 8

Which statement evaluates multiple conditions and executes corresponding blocks of code?

Accepted Answer

switch statement

Answer

loop statement

Answer

break statement

Answer

if statement

Question 9

Which keyword can be used to immediately exit a loop?

Accepted Answer

break

Answer

return

Answer

exit

Answer

continue

Question 10

Which operator is used to compare the strict equality of two values?

Accepted Answer

===

Answer

==

Answer

=

Question 11

Which keyword is used to declare a constant variable?

Accepted Answer

const

Answer

declare

Answer

var

Answer

let

Question 12

Which keyword is used to define a reusable block of code?

Accepted Answer

function

Answer

method

Answer

def

Answer

create

Question 13

Which operator can be used to conditionally execute a statement based on a boolean value?

Accepted Answer

ternary operator

Answer

switch statement

Answer

if statement

Answer

while loop

Question 14

Which statement can be used to handle exceptions in JavaScript?

Accepted Answer

try...catch

Answer

if...else

Answer

while...do

Question 15

Which control flow statement executes a block of code if a given condition is true?

Accepted Answer

if statement

Answer

while loop

Answer

switch statement

Answer

for loop

Question 16

What is the primary purpose of the 'break' keyword within a loop or switch statement?

Accepted Answer

To immediately terminate the execution of the loop or switch statement

Answer

To continue the execution of the loop or switch statement

Answer

To increment the loop counter

Question 17

Which logical operator returns 'true' if both operands are 'true'?

Accepted Answer

&&

Answer

||

Answer

!

Question 18

Explain the key difference between the '==' and '===' equality operators in JavaScript?

Accepted Answer

'==' performs type coercion, while '===' performs strict equality

Answer

'==' performs strict equality, while '===' performs type coercion

Answer

There is no difference between '==' and '==='

Question 19

Which control flow structure is designed to execute a block of code a fixed number of times?

Accepted Answer

for loop

Answer

while loop

Answer

do-while loop

Question 20

Provide the correct syntax for a 'for-in' loop in JavaScript.

Accepted Answer

for (variable in object)

Answer

for in (variable, object)

Answer

for of (variable in object)

Answer

for (variable of object)

Question 21

Which control flow statement is primarily used to handle exceptional situations or errors?

Accepted Answer

try-catch statement

Answer

if-else statement

Answer

switch statement

Answer

while loop

Question 22

What is the primary purpose of the '?' and ':' operators in JavaScript?

Accepted Answer

To conditionally assign a value to a variable based on a specified condition

Answer

To increment and decrement variables

Answer

To compare two values

Answer

To perform logical AND and OR operations

Question 23

Which of the following **is** a valid conditional statement in JavaScript?

Accepted Answer

if (condition) { statement }

Answer

when condition then statement

Answer

condition if { statement }

Answer

if [condition] then { statement }

Question 24

What is the output of the following JavaScript code? 
const age = 18; 
if (age >= 18) { console.log('Adult'); } else { console.log('Minor'); }

Accepted Answer

Adult

Answer

Minor

Answer

0

Answer

undefined

Question 25

What is the output of the following JavaScript code? 
let sum = 0; 
for (let i = 1; i <= 5; i++) { sum += i; } 
console.log(sum);

Accepted Answer

15

Answer

undefined

Answer

0

Answer

5

Question 26

Which of the following is a valid switch statement in JavaScript?

Accepted Answer

switch (variable) { case value1: { statement1; } break; case value2: { statement2; } break; default: { statement3; } break; }

Answer

case variable { value1: statement1; value2: statement2; default: statement3; }

Question 27

Which of the following is a valid JavaScript operator for logical AND?

Accepted Answer

&&

Answer

&

Answer

||

Answer

|

Question 28

What is the output of the following JavaScript code? 
let x = 5; 
let y = true; 
if (x < 10 && y) { console.log('Condition met'); }

Accepted Answer

Condition met

Answer

undefined

Answer

0

Answer

Condition not met

Question 29

Which of the following is a valid JavaScript operator for incrementing a variable by 1?

Accepted Answer

++

Answer

-=

Answer

+=

Answer

--

Question 30

What is the output of the following JavaScript code: 
```javascript 
let x = 5;  
x++;  
console.log(x); 
```

Accepted Answer

6

Answer

5

Answer

7

Answer

undefined

Question 31

Which statement is used to execute a block of code if a condition is true?

Accepted Answer

if

Answer

switch

Answer

while

Answer

for

Question 32

Which loop structure is used when the number of iterations is known?

Accepted Answer

for

Answer

foreach

Answer

while

Answer

do-while

Question 33

What is the purpose of the 'break' statement in a loop?

Accepted Answer

To exit the loop immediately

Answer

To restart the loop

Answer

To skip the current iteration

Answer

To continue the loop

Question 34

Which statement is used to select a block of code to execute based on a value?

Accepted Answer

switch

Answer

while

Answer

for

Answer

if

Question 35

What is the result of the following code: if (true && false) { ... }?

Accepted Answer

The code block is not executed

Answer

The code block is executed twice

Answer

The code block is executed infinitely

Answer

The code block is executed once

Question 36

Which of the following is NOT a valid JavaScript control flow statement?

Accepted Answer

goto

Answer

while

Answer

if

Answer

switch

Question 37

What is the output of the following code: for (let i = 0; i < 5; i++) { console.log(i); }?

Accepted Answer

0, 1, 2, 3, 4

Answer

1, 2, 3, 4, 5

Answer

1, 3, 5

Answer

0, 2, 4

Question 38

Which of the following is the correct syntax for a 'while' loop in JavaScript?

Accepted Answer

while (condition) { ... }

Answer

{ while condition }

Answer

while condition { ... }

Question 39

What is the purpose of the 'default' case in a switch statement?

Accepted Answer

To specify the code to execute if none of the other cases match

Answer

To exit the switch statement

Answer

To execute the first case

Question 40

Which of the following is the correct syntax for an 'if' statement in JavaScript?

Accepted Answer

if (condition) { statement }

Answer

if condition { statement }

Answer

if (condition): statement

Answer

if (statement) { condition }

Question 41

What is the primary purpose of the 'switch' statement in JavaScript?

Accepted Answer

To execute different code blocks based on the value of a variable.

Answer

To loop through an array of values.

Answer

To handle errors and exceptions.

Answer

To define a function with multiple possible return values.

Question 42

Which of the following is NOT a valid loop type in JavaScript?

Accepted Answer

while until

Answer

while

Answer

do...while

Answer

for

Question 43

Which logical operator returns 'true' only if BOTH operands are 'true'?

Accepted Answer

&& (and)

Answer

? (ternary)

Answer

!(not)

Answer

|| (or)

Question 44

Which keyword is used to immediately stop the execution of a loop in JavaScript?

Accepted Answer

break

Answer

stop

Answer

exit

Answer

halt

Question 45

What is the key difference between an 'if' statement and an 'if...else' statement?

Accepted Answer

An 'if...else' statement provides an alternative block of code to execute if the initial condition is false.

Answer

An 'if...else' statement is always more efficient than a simple 'if' statement.

Answer

An 'if' statement can have multiple conditions, while 'if...else' cannot.

Question 46

Which of the following represents a valid example of a ternary operator in JavaScript?

Accepted Answer

condition ? trueValue : falseValue

Answer

if (condition) { trueValue } else { falseValue }

Answer

switch (condition) { case true: trueValue; case false: falseValue }

Answer

Math.max(condition, trueValue, falseValue)

Question 47

Which JavaScript keyword is used to skip the current iteration of a loop and continue to the next one?

Accepted Answer

continue

Answer

skip

Answer

break

Answer

Question 48

What is the main purpose of the 'default' case in a 'switch' statement?

Accepted Answer

To provide a code block that executes if none of the other 'case' conditions match the switch expression.

Answer

To immediately exit the 'switch' statement.

Answer

To execute code if the switch expression is considered 'truthy' (true-like).