Скачать с ютуб Resolving Input Reading Issues in MFC C++: Simplifying with CString в хорошем качестве

Resolving Input Reading Issues in MFC C++: Simplifying with CString

Learn how to efficiently capture user input from an edit box in an MFC C++ application using CString, simplifying your math operations. --- This video is based on the question https://stackoverflow.com/q/69857519/ asked by the user 'Bela' ( https://stackoverflow.com/u/17338514/ ) and on the answer https://stackoverflow.com/a/69863090/ 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: Taking input from editbox as displaying the result 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. --- Resolving Input Reading Issues in MFC C++: Simplifying with CString When developing applications with the Microsoft Foundation Classes (MFC) in C++, it's not uncommon to encounter challenges when handling user input. A common scenario involves taking a mathematical expression from an edit box and calculating its result. If you've stumbled upon issues reading input from an edit box within an MFC program, this guide will guide you through a streamlined solution, eliminating unnecessary complexity in your code. The Problem at Hand In the intended application, the user is supposed to enter a mathematical expression into an edit box (referred to as IDC_EDIT1). The original code attempts to read this input into a char array, which can complicate character manipulation for mathematical computation. Here’s a snippet from the earlier implementation: [[See Video to Reveal this Text or Code Snippet]] Unfortunately, this approach has its drawbacks, particularly with how MFC handles string types. The key confusion arises in the initial lines of code, making this the area we need to address. The Solution: Utilizing CString Instead of using a character array to read input from the edit box, MFC provides a more efficient and simpler way through the CString class. This class is specially designed to handle strings and provides a variety of useful methods that facilitate string manipulation. Here’s the revised implementation that we recommend: [[See Video to Reveal this Text or Code Snippet]] Breakdown of the Solution Replacing char Array: Instead of defining a char input[50];, we are defining a CString input;. This approach avoids many problems associated with Char arrays, such as size limits and manual memory management. Reading Input from Edit Box: The line GetDlgItemText(IDC_EDIT1, input); reads the content from the edit box directly into the CString object input. This method is simple and avoids casting issues. Getting the Length: With len = input.GetLength();, you can easily get the length of the input without worrying about null termination or buffer overruns that can occur with char arrays. Displaying Results: The computed result (mCurVal) is formatted and displayed back in the edit box using SetDlgItemText(IDC_EDIT1, s);. Here, s.Format() allows you to specify the formatting, which is particularly useful for maintaining the accuracy to two decimal places. Benefits of Using CString Simplification: The transition to CString simplifies string handling and minimizes error potential in handling raw character arrays. Automatic Memory Management: CString takes care of memory allocations and deallocations, reducing the risks associated with manual memory management. Rich Functionality: MFC's CString class provides various built-in methods for string operations, making it more versatile than traditional character arrays. Conclusion When working with MFC C++, simplifying your input handling can prevent errors and enhance efficiency. By leveraging CString to read input from an edit box, you eliminate many common pitfalls associated with character arrays. This not only makes your code cleaner but also allows you to focus on what matters most: delivering a functional application that processes mathematical expressions seamlessly. By following the steps outlined in this guide, you should now have a more robust foundation for reading user input in your MFC programs. Happy coding!