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Parameters & Arguments: Buggy Code II in JavaScript - Time Complexity: O(1)


Inside the code editor we've tried to write a function that takes a person's name as argument and prints a tailored welcome message for that person.

Then, we welcomed Andy and John by calling the function for each of them.

So when we ran the code, we expected it to print:

Welcome, Andy!
Welcome, John!

but it seems like we made some mistakes because when we run our code, it prints:

Welcome, Andy!
Welcome, Andy!

Assignment:

Your task is to fix our code such that no errors will be produced and it will print the desired output.

Understanding the Problem

The core challenge here is to ensure that the function correctly prints a personalized welcome message for each name passed to it. The significance of this problem lies in understanding how function parameters and arguments work in JavaScript. A common pitfall is reusing variables or not properly passing arguments, which can lead to unexpected results.

Approach

To solve this problem, we need to ensure that our function correctly accepts a parameter and uses it within the function body to print the desired message. Let's break down the steps:

  1. Define a function that takes a single parameter, name.
  2. Within the function, use the parameter to construct and print the welcome message.
  3. Call the function with different arguments to test if it prints the correct messages.

Initial Naive Solution

Initially, we might write a function like this:

function welcomeMessage(name) {
  console.log("Welcome, " + name + "!");
}

welcomeMessage("Andy");
welcomeMessage("John");

This code should work correctly, but if we encounter issues, it might be due to how we are calling the function or how the function is defined.

Optimized Solution

Given the simplicity of the problem, the initial solution is already optimal. However, let's ensure that we understand why it works and how to avoid common mistakes:

  • Ensure the function parameter is used correctly within the function.
  • Ensure each function call passes a different argument.

Algorithm

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

  1. Define the function welcomeMessage with a parameter name.
  2. Inside the function, use console.log to print the message "Welcome, " followed by the value of name and an exclamation mark.
  3. Call the function twice with different arguments ("Andy" and "John").

Code Implementation

// Define the function with a parameter 'name'
function welcomeMessage(name) {
  // Print the welcome message using the parameter
  console.log("Welcome, " + name + "!");
}

// Call the function with different arguments
welcomeMessage("Andy"); // Expected output: Welcome, Andy!
welcomeMessage("John"); // Expected output: Welcome, John!

Complexity Analysis

The time complexity of this solution is O(1) because the function performs a constant amount of work regardless of the input size. The space complexity is also O(1) as we are not using any additional data structures that grow with the input size.

Edge Cases

Potential edge cases include:

  • Passing an empty string as the name.
  • Passing a non-string value as the name.

Our function handles these cases gracefully by simply printing the value passed to it:

welcomeMessage(""); // Expected output: Welcome, !
welcomeMessage(123); // Expected output: Welcome, 123!

Testing

To test the solution comprehensively, we should include a variety of test cases:

  • Normal cases with typical names.
  • Edge cases with empty strings or non-string values.

We can use a testing framework like Jest or simply run the function with different inputs to verify the outputs.

Thinking and Problem-Solving Tips

When approaching such problems, consider the following tips:

  • Clearly understand the problem statement and expected output.
  • Break down the problem into smaller steps.
  • Write pseudocode before actual implementation.
  • Test your solution with various inputs, including edge cases.

Conclusion

In this blog post, we discussed how to fix a simple JavaScript function to print personalized welcome messages. We covered the problem definition, approach, algorithm, code implementation, complexity analysis, edge cases, and testing. Understanding and solving such problems is crucial for mastering function parameters and arguments in JavaScript.

Additional Resources

For further reading and practice, consider the following resources: