Скачать или смотреть Understanding Why Rust Skips Over the For Loop in Your Game Code

Discover how to troubleshoot your `Rust` for loop issue in your hangman game. Follow our step-by-step guide to understand the logic behind `pre_guessed` and ensure your code functions correctly.
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This video is based on the question https://stackoverflow.com/q/62995612/ asked by the user 'Jack Fisher' ( https://stackoverflow.com/u/13745991/ ) and on the answer https://stackoverflow.com/a/62995693/ provided by the user 'Ry-' ( https://stackoverflow.com/u/707111/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Troubleshooting Your Rust For Loop: A Guide for Beginners

If you are new to Rust and are working on a project like a hangman game, you might encounter some challenges, especially with control flow in loops. One common issue is when a for loop seems to be silently skipping execution, causing your program to behave unexpectedly. This post will help you understand why your for loop might be skipped and guide you through a solution to this problem.

The Problem

You’ve written a for loop to check whether a guessed character is already present in a vector of previously guessed characters. However, the loop isn’t executing as expected; instead of checking the vector, it simply prompts for a letter again. This can be frustrating, especially when you believe your logic is sound. Let’s take a closer look at what might be going wrong.

Understanding Your Code

In the provided code snippet, we see the function take_input, which is designed to execute the following logic:

Prompt the user to enter a letter.

Check if the letter has been guessed before by iterating over a vector called pre_guessed.

If it has been guessed, prompt the user to guess again; if not, store the new guess.

Here is a breakdown of the relevant parts of your code:

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

At this point, if pre_guessed (which is guessed_letters in your main function) is empty, the loop doesn’t execute, and the user is prompted for a letter again.

The Key Issues

Initial State of guessed_letters: When the game starts, the guessed_letters vector is empty. Therefore, the loop that checks for previously guessed letters will not run, leading to unexpected behavior.

Infinite Loop Risk: If the guess is not found in guessed_letters, the program calls take_input(pre_guessed) again, leading to a loop since the vector remains empty on each call.

The Solution

To fix this issue, you need to adjust the flow in your take_input function. Instead of checking if run is false, check if run is true when deciding whether to add the guessed letter to pre_guessed. Here’s the corrected logic in your code:

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

Here's a Step-by-Step Adjustment

Change run's Conditional Logic: Flip the logic checking the value of run. This will push the character into pre_guessed only when it is not already present.

Test for Non-Empty Vector: To prevent unnecessary loops, you might want to handle cases where users keep guessing previously provided letters.

Conclusion

By understanding the flow and state of your variables, you can debug common issues in your Rust code. Adapting your take_input function to check run appropriately should resolve the problem of the for loop being skipped. Remember, programming often involves carefully tracking variable states and their effects on control flow. Happy coding, and good luck with your hangman game!