Create A Webpage For Calculating Average Grades Using Loops

Create A Webpage for Calculating Average Grades Using Loops and Prompt Box

Create a webpage and an external JavaScript file to calculate average grades entered by the user. For this program, you will use a prompt box that gets a value from the user. The user will enter grades one after another in the prompt box, and when they want to stop, they will enter a negative number. After the user stops entering grades, display the total, number of grades, and the average. Make sure to include appropriate comments in your code, explaining each step. The program should not specify the number of grades in advance; it depends entirely on user input. Test the program with simple numbers first, ensuring the average calculation is correct. Use a clear explanation of what the program does in the webpage. Display the results using either text or an alert box. Ensure your webpage is easy to understand and user-friendly.

Paper For Above instruction

Calculating Averages Using Loops and Prompt Boxes in JavaScript

In web development, creating interactive features that engage users effectively is crucial. One common task is to collect multiple data inputs from users and analyze them, such as calculating the average of a series of grades. Using JavaScript, this process can be streamlined with loops and prompt boxes, enhancing user experience through simple, real-time interactions.

This paper discusses how to develop a webpage with an external JavaScript file that prompts users to input grades repeatedly until they choose to stop by entering a negative number. The core logic involves a loop that collects grades via the prompt box, converts string inputs into numerical values, and maintains a running total along with a count of valid grades entered. The sentinel value, a negative number, signals the loop to terminate, ensuring negative entries are excluded from calculations.

Design and Implementation

The implementation begins with creating an HTML webpage providing a user-friendly interface and a link to the external JavaScript file. The webpage explains the program’s functionality to the user, emphasizing that they should enter grades one at a time and input a negative number to stop. In the JavaScript file, variables are declared to track the total sum of grades, the count of valid grades, and the current grade input.

The core process involves a do-while or while loop, where each iteration prompts the user to input a grade. The input, received as a string, is converted into a floating-point number using parseFloat(). An if statement checks whether the entered number is negative; if so, the loop terminates without adding the negative number to the total. Otherwise, the value is added to the total, and the counter increments.

After exiting the loop, the script calculates the average by dividing the total sum by the number of grades entered. It then displays the total, count, and average either via an alert box or by updating the webpage’s content dynamically. Proper commenting throughout the code helps clarify the purpose of each segment, from variable initialization to condition checking.

Testing and Validation

Thorough testing involves entering various sequences of numbers, including positive grades and the sentinel negative number, to ensure correctness. For example, entering 80, 90, 70, and then -1 should result in an accurate total of 240, a count of three, and an average of 80.0. Special cases, such as entering only negative numbers initially, should be handled gracefully, indicating zero grades entered without attempting to divide by zero.

Results and User Experience

A clear explanation of the program's functionality, visible at the top of the webpage, enhances user understanding. Using alert boxes for results is straightforward but can be replaced with dynamic HTML updates for better user experience. Comments in the JavaScript code serve as documentation, aiding future maintenance and comprehension by other developers.

Conclusion

This approach exemplifies efficient use of JavaScript’s loops and prompt boxes for interactive data collection. It provides an educational tool for understanding control flow, data validation, and user interaction within web pages. Proper testing and user-friendly messaging ensure robustness and usability, making it a suitable exercise for students learning JavaScript basics.

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