1. What is the main purpose of a while loop in JavaScript?
Answer:
Explanation:
A while loop in JavaScript is used to execute a block of code repeatedly as long as a specified condition remains true.
2. What is the basic syntax of a while loop in JavaScript?
Answer:
Explanation:
The basic syntax of a while loop includes the while keyword followed by a condition in parentheses and a block of code in curly braces.
3. How does a while loop start its execution?
Answer:
Explanation:
A while loop starts its execution by first evaluating the condition. If the condition is true, the loop executes the block of code.
4. What happens if the condition in a while loop never becomes false?
Answer:
Explanation:
If the condition in a while loop never becomes false, the loop will continue to execute indefinitely, resulting in an infinite loop.
5. Can you declare and initialize variables within the while loop condition?
Answer:
Explanation:
It is possible to declare and initialize variables within the while loop condition, although it is more common to do so before the loop starts.
6. What is the main difference between a while loop and a do-while loop?
Answer:
Explanation:
The main difference is that a do-while loop executes the block of code once before checking the condition, ensuring that the code block is executed at least once.
7. How can you stop the execution of a while loop?
Answer:
Explanation:
The break keyword can be used within the loop body to exit the loop prematurely and stop its execution.
8. What happens when a break statement is executed inside a while loop?
Answer:
Explanation:
When a break statement is executed inside a while loop, it terminates the loop's execution immediately and exits the loop.
9. Can a while loop contain another while loop inside it?
Answer:
Explanation:
A while loop can contain another while loop inside it, forming a nested loop structure.
10. Is it necessary for a while loop to have a body with statements?
Answer:
Explanation:
A while loop can have an empty body, though it is not common and usually not very useful.
11. How do you ensure that a while loop eventually terminates?
Answer:
Explanation:
To ensure that a while loop terminates, the condition must eventually evaluate to false. This can be achieved by modifying the condition within the loop or using a counter that changes each iteration.
12. In a while loop, when is the condition re-evaluated?
Answer:
Explanation:
In a while loop, the condition is re-evaluated after each iteration to determine if the loop should continue or terminate.
13. Can variables used in a while loop condition be modified inside the loop?
Answer:
Explanation:
Variables used in the condition of a while loop can be modified inside the loop, which is often necessary for the loop to eventually terminate.
14. What is the function of the continue statement in a while loop?
Answer:
Explanation:
The continue statement in a while loop is used to skip the rest of the current iteration and proceed directly to the next iteration.
15. Is it possible for a while loop to execute zero times?
Answer:
Explanation:
A while loop will execute zero times if its condition is false from the very beginning, as the condition is checked before the first iteration.