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LESSON 44 OF 410 · FUNCTIONS I

Return: Quiz I in JavaScript - Time Complexity: O(1)

Quiz Read the full explanation

Quiz: What would this code produce if we were to copy-paste it in a code editor and run it?

function getDouble(n) {
	n * 2
}

result = getDouble(10);
console.log(result);

Important Note:

Do not use an actual code editor to get the answer! It would defy the whole purpose of the quiz!

Pick your answer

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JAVASCRIPT · FUNCTIONS I

Quiz Forgotten Return in JavaScript, explained

Understanding the Problem

The core challenge of this problem is understanding how JavaScript functions work, particularly the return statement. The function getDouble is supposed to double the input value n, but it lacks a return statement. This is a common pitfall for beginners.

Approach

To solve this problem, we need to understand the behavior of functions in JavaScript:

  • When a function does not explicitly return a value, it implicitly returns undefined.
  • In the given code, the function getDouble performs the multiplication n * 2, but does not return the result.

Therefore, the variable result will be assigned the value undefined, and console.log(result) will print undefined.

Algorithm

Here is a step-by-step breakdown of the algorithm:

  1. Define the function getDouble with a parameter n.
  2. Inside the function, perform the multiplication n * 2.
  3. Since there is no return statement, the function implicitly returns undefined.
  4. Assign the result of getDouble(10) to the variable result.
  5. Print the value of result using console.log.

Code Implementation

function getDouble(n) {
    // Perform the multiplication but do not return the result
    n * 2;
}

let result = getDouble(10); // result will be undefined
console.log(result); // This will print undefined

// Corrected version of the function
function getDoubleCorrected(n) {
    return n * 2; // Explicitly return the result
}

let correctedResult = getDoubleCorrected(10); // correctedResult will be 20
console.log(correctedResult); // This will print 20

Complexity Analysis

The time complexity of this function is O(1) because it performs a single multiplication operation, regardless of the input size. The space complexity is also O(1) as it uses a constant amount of space.

Edge Cases

Potential edge cases include:

  • Passing non-numeric values to the function, which would result in NaN (Not-a-Number).
  • Passing very large or very small numbers, which could lead to precision issues.

Testing

To test the solution comprehensively, consider the following test cases:

  • Simple case: getDouble(10) should return 20.
  • Edge case: getDouble("a") should return NaN.
  • Edge case: getDouble(0) should return 0.

Thinking and Problem-Solving Tips

When approaching such problems, always ensure that your functions have explicit return statements if they are supposed to return a value. Practice by solving similar problems and studying how functions work in JavaScript.

Conclusion

In this problem, we learned the importance of the return statement in JavaScript functions. By understanding this concept, we can avoid common pitfalls and write more reliable code.

Additional Resources

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