Javascript Functions

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Questions and Answers

Which statement correctly describes the primary benefit of using functions in programming?

Functions create a completely isolated environment, preventing any interaction between different parts of the program.
Functions allow for the reuse of code blocks, reducing redundancy and improving maintainability. (correct)
Functions automatically optimize code for faster execution, regardless of their content.
Functions enable direct manipulation of hardware resources, enhancing system-level control.

What is the expected behavior when a variable is declared within a function in JavaScript?

The variable is accessible within the function and all functions called by it.
The variable is only accessible within the function where it is declared. (correct)
The variable's scope extends to the entire script, but it can only be read, not modified, outside the function.
The variable is globally accessible and can be modified by any part of the script.

Consider a scenario where a function needs to display a user's login status. Which approach best utilizes the benefits of functions?

Employing a separate script to monitor login events and trigger alerts independently of the main application.
Relying on global variables to track the login status and using conditional statements to display the appropriate message directly in the main program flow.
Creating a single function to handle the display logic, which is then called whenever the login status changes. (correct)
Duplicating the code for displaying the login status across every location where it's needed.

If a function `calculateArea(length, width)` is defined but called without any arguments (i.e., `calculateArea()`), what might happen depending on the programming language and context?

The function will execute using <code>undefined</code> or <code>null</code> values for <code>length</code> and <code>width</code>, potentially leading to unexpected results or errors. (A) Signup and view all the answers

What is the primary purpose of parameters in a function declaration?

To enable the function to receive input values that can be used during its execution. (C) Signup and view all the answers

Which of the following accurately describes the concept of a 'function body'?

The block of code enclosed in curly braces <code>{}</code> that contains the instructions to be executed when the function is called. (B) Signup and view all the answers

In what way do functions contribute to improving code maintainability, especially in large projects?

Functions centralize specific tasks, making it easier to update or fix code in one place rather than many. (B) Signup and view all the answers

How does using local variables within functions enhance code reliability?

Local variables prevent naming conflicts and unintended modifications by isolating variable scope to the function where they are declared. (B) Signup and view all the answers

Consider a function designed to validate user input. What would be the most effective approach to handle invalid input within the function?

Throw an exception or return a specific error code, signaling that the input is invalid and allowing the calling code to handle the error gracefully. (A) Signup and view all the answers

Which of the following scenarios best illustrates the use of a function to avoid code duplication and improve code organization?

Defining a function to perform a common task, such as formatting dates, and calling it from multiple places in the application. (A) Signup and view all the answers

Flashcards

What are Functions?

Reusable blocks of code that perform a specific task.

What is Function Declaration?

The process of creating a function using the function keyword.