1. What is the purpose of the switch statement in JavaScript?
Answer:
Explanation:
The switch statement is used to perform different actions based on different conditions. It allows the execution of a block of code among many alternatives.
2. What is the correct syntax for a switch statement in JavaScript?
Answer:
Explanation:
The correct syntax for a switch statement includes the switch keyword followed by an expression in parentheses and a series of case statements inside curly braces.
3. How does JavaScript match a case in a switch statement?
Answer:
Explanation:
JavaScript matches a case in a switch statement using strict equality, meaning both the value and the type must be the same.
4. What keyword is used to define a default case in a switch statement?
Answer:
Explanation:
The default keyword is used to specify the default case in a switch statement, which is executed if no case matches.
5. Can a switch statement include multiple cases for the same block of code?
Answer:
Explanation:
Multiple cases can be used for the same block of code in a switch statement. They are typically stacked together above a single block.
6. What is the role of the break keyword in a switch statement?
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Explanation:
The break keyword stops the execution of the current case and exits the switch statement.
7. What happens if the break keyword is omitted in a switch case?
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Explanation:
If the break keyword is omitted, the execution continues with the next case (fall-through behavior).
8. Is it mandatory to have a default case in a switch statement?
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Explanation:
The default case in a switch statement is optional. It is executed if no case matches, but its absence does not invalidate the switch statement.
9. Can the default case be placed at the beginning of a switch statement?
Answer:
Explanation:
The default case can be placed anywhere in a switch statement, but if it's not at the end, it should include a break statement to prevent fall-through.
10. What type of values can be used for cases in a switch statement?
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Explanation:
In a switch statement, cases can use both strings and numbers as values. JavaScript evaluates them using strict comparison.
11. Can a switch statement be nested inside another switch statement?
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Explanation:
A switch statement can be nested inside another switch statement, allowing for more complex decision structures.
12. How does JavaScript handle a case value that is an expression?
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Explanation:
JavaScript evaluates the expressions in case values at runtime, allowing dynamic matching in the switch statement.
13. How is a switch statement different from a series of if-else statements?
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Explanation:
A switch statement is more efficient and cleaner when you have many distinct cases to handle, compared to using multiple if-else statements.
14. Can the cases in a switch statement be non-sequential?
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Explanation:
The cases in a switch statement can be in any order; they don't have to be sequential or in any specific order.
15. Is it possible to use a variable as a case value in a switch statement?
Answer:
Explanation:
Variables can be used as case values in a switch statement, allowing for dynamic and flexible case evaluation.