Debugging C Code: Fixing the Issue of Random Numbers in Structure Display

Learn how to debug C code that mistakenly displays random numbers instead of user data, including an improved solution with clear explanations. --- This video is based on the question https://stackoverflow.com/q/64871664/ asked by the user 'Samuel Njogu' ( https://stackoverflow.com/u/14653237/ ) and on the answer https://stackoverflow.com/a/64872110/ provided by the user 'Jabberwocky' ( https://stackoverflow.com/u/898348/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions. Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: C structures displaying numbers rather than user data Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l... The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license. If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com. --- Debugging C Code: Fixing the Issue of Random Numbers in Structure Display When working on C programming, it's common to encounter issues, especially when dealing with user input and data structures. One prevalent problem is when your code is expected to display user-input data but instead prints random numbers. This blog will break down a specific case involving a code snippet meant for managing books, illustrating the mistakes and providing a corrected solution that illustrates best practices in C programming. The Problem: Random Numbers Instead of User Data In this case, a user attempted to create a program to manage book details. However, the output was displaying random numbers instead of the book names and authors as intended. The confusion stemmed from improper memory allocation and incorrect handling of string data in C. Let's dissect the original code to understand where things went wrong. Original Code Issues Incorrect Structure Declaration: The code originally declared the structure books with pointers to strings but did not allocate memory correctly for those strings, leading to undefined behavior when they were printed. Memory Management Issues: The code attempted to manipulate data using pointer arithmetic, making it harder to read and debug. Use of Deprecated Functions: The gets() function was used, which is known to be unsafe as it doesn't check the buffer size and can lead to buffer overflows. Initialization of Variables: Improper variable initialization and memory management contributed to the issues observed in code execution. The Solution: A Better Approach to Manage Book Data Given the analysis above, here’s a revised version of the code that resolves these problems. Let's go through the changes step-by-step: Step 1: Revise the Structure Declaration Instead of using a pointer array for strings, we simply use arrays directly within the structure. This approach is more straightforward and avoids the risk of memory corruption. [[See Video to Reveal this Text or Code Snippet]] Step 2: Proper Memory Allocation We start with no books allocated and use realloc each time we add a new book, ensuring we manage memory dynamically: [[See Video to Reveal this Text or Code Snippet]] Step 3: Collecting User Input Provide a user-friendly interface while ensuring we handle input correctly: [[See Video to Reveal this Text or Code Snippet]] Step 4: Displaying the Books To show the books correctly, loop through the allocated books array and print the results: [[See Video to Reveal this Text or Code Snippet]] Final Code Here’s the complete working version of the program: [[See Video to Reveal this Text or Code Snippet]] Conclusion Debugging code in C can be challenging, especially with the nuances of memory management and input handling. By ensuring proper memory allocation, avoiding deprecated functions, and using straightforward approaches for data handling, you can effectively write reliable C applications. Remember to conduct thorough testing and review any potential improvements for robustness, such as error checking for memory reallocation and safer input functions. With this guide, you should now be equipped to tackle similar issues in your C programming endeavors. Happy coding!