magic-numbers

问题 I've just completed writing a program for a programming class, and I want to avoid use of magic numbers, so here's my question: In the function below, would my array indexers be considered magic numbers? Code: string CalcGrade(int s1, int s2, int s3, double median) { const int SIZE = 23; const int LETTER_GRADE_BARRIERS[SIZE] = { 400, 381, 380, 361, 360, 341, 340, 321, 320, 301, 300, 281, 280, 261, 260, 241, 240, 221, 220, 201, 200, 181, 180 }; double finalGrade; string letterGrade; finalGrade

问题 After googling, I found that Magic numbers can be used to identify the content type of a file. In my program, I would like to validate the file content type on server side. My client side code : <form action="/Home/Index" method="post" enctype="multipart/form-data"> <input type="file" id="inputFile" value="" onchange="readFileContent(this)" /> <input type="submit" value="Submit" /> </form> function readFileContent(input) { if (input.files && input.files[0]) { reader = new FileReader(); reader

问题 I am designing a binary file format from scratch, and I would like to include some magic bytes at the beginning so that it can be identified easily. How do I go about choosing which bytes? I am not aware of any central registry of magic numbers, so is it just a matter of picking something fairly random that isn't already identified by, say, the file command on a nearby UNIX box? 回答1: Stay away from super-short magic numbers. Just because you're designing a binary format doesn't mean you can't

问题 How do I store numbers in an Access column and then associate some meaningful string to each value? Because I don't want to be seeing raw numbers when I can define the meaning of each value once at for all, and have those meanings displayed in the Datasheet View, like: ID Name Type 1 Jack 1 (Friend) 2 Jill 1 (Friend) 3 Diago 2 (Enemy) 4 Sally 3 (Colleague) 回答1: You probably want at least two different tables. One that has the ID and Name of the people, and another table with the Type and

问题 So I made a short Python script to launch files in Windows with ambiguous extensions by examining their magic number/file signature first: https://superuser.com/a/317927/13889 https://gist.github.com/1119561 I'd like to compile it to a .exe to make association easier (either using bbfreeze or rewriting in C), but I need some kind of user-friendly config file to specify the matching byte strings and program paths. Basically I want to put this information into a plain text file somehow: magic

问题 0x10b : PE32 executable 0×107 : ROM image 0x20b : PE32+ (64 bit) executable What is the ROM image ? 回答1: Interesting question, I've dabbled with manipulating PE files but never noticed that. Here's what I believe they are used for: A ROM image can be executed 'in place' (XIP), if you search MSDN for "rom image", you'll find a number of references to it in the Windows Mobile and older Windows CE tools, e.g. Rom Image Creation. A ROM image can thus be executed directly from the ROM without

问题 This question was migrated from Information Security Stack Exchange because it can be answered on Stack Overflow. Migrated 6 years ago . Files are categorized by file-extension. So my question is, how to identify the file type even the file extension has been changed. For example, i have a video file with name myVideo.mp4 , i have changed it to myVideo.txt . So if i double-click it, the preferred text editor will open the file, and won't open the exact content. But, if i play myVideo.txt in a

问题 I have a project on GitHub that I work on both in the office at home. For about 2 months it was working fine on both machines. Then two weeks ago, it stopped running on my home PC, but still works fine on my work PC . This is the error I get: :app:shrinkDebugMultiDexComponents FAILED FAILURE: Build failed with an exception. What went wrong: Execution failed for task ':app:shrinkDebugMultiDexComponents'. java.io.IOException: Can't read [D:\dev\gitRepo\app\android\app\build\intermediates\multi

问题 I have seen this in legacy code and in some .NET open source projects. I can't imagine a reason to do this. Just using "null" seems so much easier to me. Example: public class Category { int parentID; bool HasParent { get { return parentID != -1; } } } versus public class Category { int parentID; bool HasParent { get { return parentID != null; } } } 回答1: Because to have a "null" value, the type must be nullable. This works fine for reference types (any class you define and the standard

问题 How can I create a reserved pointer value? The context is this: I have been thinking of how to implement a data structure for a dynamic scripting language (I am not planning on implementing this - just wondering how it would be done). Strings may contain arbitrary bytes, including NUL. Thus, it is necessary to store the value separately. This requires a pointer (to point to the array) and a number. The first trick is that if the pointer is NULL, it cannot possibly be a valid string, so the