Javascript loops MCQ - Quiz

Q: One of the unique characteristics of an interpreter in relation to the for loop is that

A. Before each iteration, the interpreter evaluates the variable expression and assigns the name of the property
B. The iterations can be infinite when an interpreter is used
C. The body of the loop is executed only once
D. The iteration is finite when an interpreter is used

Correct Option: A
Explanation:

The interpreter converts the source code into machine code, line by line, and halts when it encounters an error.
Before processing each line, the interpreter evaluates the variable expression and assigns the property name (a string value) to it.

Q: What is the purpose of the continue keyword in the following JavaScript code snippet?

while (a != 0)
{
   if (a == 1) 
       continue;
   else 
       a++;
}

A. The continue keyword restarts the loop
B. The continue keyword skips the next iteration
C. The continue keyword skips the rest of the statements in that iteration
D. The continue keyword breaks out of the loop

Correct Option: C
Explanation:

The continue statement is used to skip the current iteration and move to the next one, unlike the break statement which terminates the loop.

Q: What happens if the body of a for/in loop deletes an unenumerated property?

A. The property will be stored in a cache
B. The loop will not run
C. That property will not be enumerated
D. The property will be enumerated

Correct Option: C
Explanation:

If a property on an object is deleted during a for/in loop before it is enumerated, it will not be enumerated.
Additionally, properties that are defined within the body of the loop will typically not be included in the enumeration.

Q: What are the three most important manipulations performed on a loop variable in a for loop?

A. Updation, Incrementation, Initialization
B. Initialization,Testing, Updation
C. Testing, Updation, Testing
D. Initialization,Testing, Incrementation

Correct Option: B
Explanation:

The three critical manipulations of a loop variable in a for loop are initialization, testing, and updating.
The loop first initialises the variable, then tests the condition, and finally increments its value after executing the statement.

Q: Which of the following keywords is not a statement?

A. Debugger
B. With
C. if
D. use strict

Correct Option: D
Explanation:

The "use strict" directive is a way to opt-in to a restricted variant of JavaScript.
The purpose of "use strict" is to indicate that the code should be executed in "strict mode".
This is a way to opt-in to a restricted variant of JavaScript, which can help you write "safer" JavaScript.

Q: What could the statement debugger in the following JavaScript code be doing?

function f(o) 
{
     if (o === undefined) debugger;
}

A. It does nothing but a simple breakpoint
B. It debugs the error in that statement and restarts the statement's execution
C. It is used as a keyword that debugs the entire program at once
D. It is used to find error in the statement

Correct Option: A
Explanation:

The debugger statement typically doesn't have any effect when executed.
However, if a debugging program is active and running, it may trigger some type of debugging action.
Essentially, this statement acts like a breakpoint, which means the execution of JavaScript code will be halted, and you will be able to examine variable values using the debugging tools.

Q: When an exception is thrown, what step will the interpreter take?

A. The interpreter stops its work
B. The interpreter throws another exception
C. The interpreter jumps to the nearest enclosing exception handler
D. The interpreter throws an error

Correct Option: C
Explanation:

When an exception is raised in a jump statement, the interpreter will navigate to the closest exception handler, this handler could be located either in the same function or in an outer function that invoked it.

Q: What happens if the for/in loop body deletes a property that has not yet been enumerated?

A. The property will be stored in a cache
B. The loop will not run
C. That property will not be enumerated
D. The property will be enumerated

Correct Option: C
Explanation:

If the body of a for/in loop removes a property that has not yet been enumerated, that property will not be included in the loop.
Additionally, if the body of the loop adds new properties to the object, those properties will typically not be enumerated.

Q: What is the purpose of the continue keyword in the following JavaScript code snippet?

while (a != 0)
{
   if (a == 1) 
       continue;
   else 
       a++;
}

A. The continue keyword restarts the loop
B. The continue keyword skips the next iteration
C. The continue keyword skips the rest of the statements in that iteration
D. The continue keyword breaks out of the loop

Correct Option: C
Explanation:

The continue keyword causes the loop to move on to the next iteration from the point at which it is encountered, whereas the break keyword exits the loop entirely.

Q: What could the statement debugger in the following JavaScript code be doing?

function f(o) 
{
     if (o === undefined) debugger;
}

A. It does nothing but a simple breakpoint
B. It debugs the error in that statement and restarts the statement's execution
C. It is used as a keyword that debugs the entire program at once
D. It is used to find error in the statement

Correct Option: A
Explanation:

The debugger statement typically has no effect. However, if a debugger is available and running, the implementation may (but is not required to) perform some kind of debugging action.
In practice, this statement functions like a breakpoint, causing the execution of JavaScript code to stop and allowing you to use the debugger to print out the values of variables.

Javascript loops MCQ - Quiz

One of the unique characteristics of an interpreter in relation to the for loop is that

What is the purpose of the `continue` keyword in the following JavaScript code snippet?
while (a != 0) { if (a == 1) continue; else a++; }

What happens if the body of a for/in loop deletes an unenumerated property?

What are the three most important manipulations performed on a loop variable in a for loop?

Which of the following keywords is not a statement?

What could the statement debugger in the following JavaScript code be doing?
function f(o) { if (o === undefined) debugger; }

When an exception is thrown, what step will the interpreter take?

What happens if the for/in loop body deletes a property that has not yet been enumerated?

What is the purpose of the continue keyword in the following JavaScript code snippet?
while (a != 0) { if (a == 1) continue; else a++; }

What could the statement debugger in the following JavaScript code be doing?
function f(o) { if (o === undefined) debugger; }

Javascript loops MCQ - Quiz

One of the unique characteristics of an interpreter in relation to the for loop is that

What is the purpose of the continue keyword in the following JavaScript code snippet? while (a != 0) { if (a == 1) continue; else a++; }

What happens if the body of a for/in loop deletes an unenumerated property?

What are the three most important manipulations performed on a loop variable in a for loop?

Which of the following keywords is not a statement?

What could the statement debugger in the following JavaScript code be doing? function f(o) { if (o === undefined) debugger; }

When an exception is thrown, what step will the interpreter take?

What happens if the for/in loop body deletes a property that has not yet been enumerated?

What is the purpose of the continue keyword in the following JavaScript code snippet? while (a != 0) { if (a == 1) continue; else a++; }

What could the statement debugger in the following JavaScript code be doing? function f(o) { if (o === undefined) debugger; }

What is the purpose of the `continue` keyword in the following JavaScript code snippet?
while (a != 0) { if (a == 1) continue; else a++; }

What could the statement debugger in the following JavaScript code be doing?
function f(o) { if (o === undefined) debugger; }

What is the purpose of the continue keyword in the following JavaScript code snippet?
while (a != 0) { if (a == 1) continue; else a++; }

What could the statement debugger in the following JavaScript code be doing?
function f(o) { if (o === undefined) debugger; }