How to Read Words from a File into a Dynamically Allocated 2D Array in C

A detailed guide on how to read an unknown number of words from a file into a dynamically allocated 2D array using C, including key concepts and code examples. --- This video is based on the question https://stackoverflow.com/q/68936395/ asked by the user 'PaYeeTeX' ( https://stackoverflow.com/u/12402473/ ) and on the answer https://stackoverflow.com/a/68976102/ provided by the user 'Yun' ( https://stackoverflow.com/u/16632281/ ) 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: Reading the words of a file into a dynamic 2D array 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. --- Reading Words from a File into a Dynamically Allocated 2D Array in C When working with files in C, a common task is to read the contents and store them in a data structure for further processing. One challenge arises when the size of the input file is not known beforehand. This guide will guide you through a practical solution to dynamically read every word from a file and store it in a 2D array, enabling your program to handle variable-length input efficiently. Let's break down the core problem and solution. The Problem You want to read a file, and as you read it, dynamically allocate memory to store every word in a 2D array. Since the file size is unknown, you need to ensure that memory can grow as you add new words. Key Challenges: Dynamic Memory Allocation: The program must allocate more space as it reads more words. Handling Large Words: Some words might exceed the predefined buffer size, requiring careful handling during reading. The Solution: Implementing a State Machine To tackle the problem efficiently, we can use a state machine approach that switches between two states: reading whitespace and reading non-whitespace characters. State Machine States State 1: Whitespace Action: Continue reading whitespace until a non-whitespace character is encountered. State 2: Non-Whitespace (Word) Action: Continue reading until whitespace is encountered, copying the word to the array. Implementation Steps Here’s how to implement the solution: Read Input Buffer: Use a buffer to read lines of the file. Track Word Segments: As words may span multiple buffers, keep track of the word size as you read. Expand Memory: As new words are added, use dynamic memory allocation (with realloc) to ensure you have enough space. Example Code Below is a simplified implementation to achieve this: [[See Video to Reveal this Text or Code Snippet]] Explanation of the Code The wordArray struct holds the dynamic array of words and its count. The wordArrayRead function reads the file line by line, identifies words, and stores them in the dynamic array. It adjusts the size when necessary. The wordArrayPrint function prints the words stored and cleans up allocated memory to prevent leaks. Note The given program reads input from standard input. To test with a file, you can redirect input using the command line like so: [[See Video to Reveal this Text or Code Snippet]] Conclusion Reading words from a file and storing them in a dynamically allocated 2D array in C can be efficiently managed by implementing a state machine and careful memory management. By following the outlined steps and utilizing the provided code, you can extend this functionality to suit your needs effectively. If you have any questions or need further assistance, feel free to comment below!