Скачать или смотреть Resolving the 2D Array Value Duplication Issue in C Programming

Discover how to fix the issue of values in a `2D array appearing twice` when assigned just once in C.
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This video is based on the question https://stackoverflow.com/q/64314989/ asked by the user 'Gus' ( https://stackoverflow.com/u/10606321/ ) and on the answer https://stackoverflow.com/a/64315165/ provided by the user 'Mikheil Zhghenti' ( https://stackoverflow.com/u/5119030/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Understanding the Problem: Duplicated Values in 2D Arrays

If you've ever worked with 2D arrays in C programming and faced the frustrating issue of a value appearing in multiple locations after a single assignment, you're not alone. This problem arises due to incorrect indexing within your loops when traversing the array, leading to unexpected outputs. Let's dive into the root cause of the issue and how to solve it effectively.

The Code That Leads to Confusion

Consider the following code snippet which sets up a 2D array and modifies one of its entries:

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When you run this code, you might expect to see just a single character @ at coordinates [49][0], but you might actually see it appear twice or more in the output. This leads to confusion as to why setting one value results in multiple appearances.

Unpacking the issue

Incorrect Loop Condition

One of the fundamental mistakes in the code arises from the way the print_display function accesses the elements of the disp array. The loops are incorrectly structured, which results in accessing the array wrongfully. Instead of iterating y for rows and x for columns, the current loop uses y for the height (index) and x for the width (index), leading to incorrect indexing.

Suggested Changes

Let’s correct the loop indices, ensuring that we iterate over the dimensions correctly:

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Full Corrected Code

Here’s the revised program that addresses the value duplication issue effectively:

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

Conclusion

The apparent duplication of values in your 2D array was the result of improper indexing during iteration. By switching the loop structures in your print_display function to accurately reflect dimensions, you can ensure that values are set and displayed correctly. Always remember that clear and proper indexing is key to successfully managing data structures like arrays in C programming.

Now, with this understanding and proper indexing in place, you can confidently proceed to manipulate your 2D arrays without encountering similar issues. Happy coding!