Скачать или смотреть How to Fix Your Loop in Java for Input Validation and Limiting Entries

Learn how to properly set conditions for stopping a loop in Java when accepting user input, ensuring that numbers are within a specific range and limiting the number of entries.
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This video is based on the question https://stackoverflow.com/q/64160130/ asked by the user 'Navo Shankar' ( https://stackoverflow.com/u/10654527/ ) and on the answer https://stackoverflow.com/a/64160222/ provided by the user 'Mauricio Guzinski' ( https://stackoverflow.com/u/2573717/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Fix Your Loop in Java for Input Validation and Limiting Entries

When writing a program that takes user input, it’s crucial to enforce rules about what is acceptable input. This not only ensures that your program runs smoothly but also provides a better user experience. In this guide, we will address a common issue encountered by beginners in Java programming – how to properly structure a loop for user input that stops under specific conditions.

The Problem

You want to create a loop that:

Accepts numbers only between 1 and 50.

Stops if the user enters a number that is less than 1 or greater than 50.

Limits the number of inputs to 20.

However, your current implementation has two main issues:

It can enter an infinite loop if the user keeps entering valid numbers.

It does not limit the number of inputs effectively.

Let’s take a closer look at your current loop to identify the changes we need to make.

Understanding Your Current Code

Here’s a simplified version of your code:

[[See Video to Reveal this Text or Code Snippet]]

Issues Identified:

Infinite Loop: Your loop will continue indefinitely if valid numbers are entered repeatedly.

Unused Index: The inner loop (while(i < 19)) doesn't effectively utilize the index for storing additional numbers.

The Solution

To fix these issues, you need to modify the loop's conditional checks. Follow these steps:

1. Combine Conditions in the While Loop

Change your main loop condition to check for both input validity and the maximum number of inputs:

[[See Video to Reveal this Text or Code Snippet]]

2. Increment the Index

Make sure to increment the index variable i after each valid input so that the next input can be stored appropriately.

3. Sample Code

Here’s a revised version of your code that includes these suggestions:

[[See Video to Reveal this Text or Code Snippet]]

4. Explanation of Changes

The loop now checks all required conditions simultaneously, effectively controlling when to stop.

By incrementing i within the loop, you ensure that each valid input is stored correctly in the nums array until you reach 20 inputs or an invalid input.

Conclusion

With these changes, you can successfully manage user input for a program in Java. By ensuring your loop exits correctly under specified conditions, you improve both the functionality and reliability of your code. Remember, good input validation is a fundamental part of writing robust applications. If you have any more questions about Java loops or need further clarification, feel free to ask!