C is a general-purpose computer programming language used for operating systems, games and other high performance work.

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How much does C help you in other languages? [duplicate]

How much does learning C to moderate level help you as a programmer. For example, does being competent in C make it easier to pick up languages as time goes on and get a better understanding of them?
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157 views

Use of for loop conditional statement unrelated to iterating variable

Is it considered decent form to write code like this: int done = 0; for (x = 0; !done; x++) { ... something involving 'x', that might end early ... if (!(x < max)) done = 1; } ...
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278 views

Including extra headers that I do not really need

I always wondered what are the effects of including not needed headers to the final executable once compiled. In my code some times I may included many different headers that I do not need (or I used ...
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7k views

usage of double pointers and n pointers?

I am familiar with basic C pointers. Just wanted to ask what is the actual use of double pointers or for that matter n pointer? #include<stdio.h> int main() { int n = 10 , *ptr , **ptr_ptr ; ...
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Regarding little endian and big endian conversion

I have a query regarding big endian and little endian. Basically the conversion is used to reverse the byte order in memory . When we need to do the conversion, do we need convert each and every ...
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210 views

Where is interface between button click and event raising defined

When I click on button, might be in windows apps, web apps, etc it has some animation to actually see it clicked and event is raised in background. I've knowledge of events and its attaching to button ...
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4answers
907 views

Data structure for file search

I've asked this question before and I got a few answers/idea, but I'm not sure how to implement them. I'm building a telecom messaging solution. Currently, I'm using a database to save my transaction/...
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1answer
147 views

Does having so many macros (#define) increase compilation time due to prolonged pre-processing?

In a very simplistic way, I understand: "Compilation" = "Pre-processing" + "Parsing" + "Linking" + "Executable" All the macros and other such pre-processing directives are taken care at the "Pre-...
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1answer
128 views

Memory usage of global versus local variables

I am a beginner in C coding. I'm writing a C code where a variable is required to be used by different functions. I want to ask whether to use a global variable and manipulate it through functions or ...
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94 views

Consistency of Undefined behavior

If there's a bug that triggers undefined behavior in a piece of code, is the undefined behavior consistent each time running it? and changes each time compiling it? For example if you had some C code ...
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1answer
244 views

Mixing OOP and Non-OOP

I'm working on a command line interface text based game. I'm writing it in C but there are various ways in which I could refactor the code by using Objective-C: using NSDictionary to allow me to ...
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1answer
188 views

What is the most efficient way to discover devices on a network?

I've been programming a C web server from scratch as an interface for controlling ESP8266 WiFi modules that I plan to use to control appliances & lighting with relays. In an attempt to make a user-...
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240 views

What would be a reason not to embed JS in C? [closed]

I'm working on an opensource application that processes JSON in C, because I would like to make it easier for people to help me in the project and because JSON is so close to JS. I want to embed a JS ...
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208 views

In C, what is an unconditional jump?

I have to fill out some documentation regarding a C project i worked on. One topic is whether I used "unconditional jumps". As far as I know, a "break" statement counts as a jump. And I have a few of ...
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3answers
239 views

Question about multidimensional arrays

I was wondering something about the multidimensional arrays and then I got a doubt about a concept, specifically about their representation on memory. For example, an array can be defined as follows. ...
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1answer
5k views

The advantage of using __attribute__((aligned( )))

I found in more than one SIMD program the instruction __attribute__((aligned(16))) . When I looked for an explanation I found The keyword attribute allows you to specify special attributes of ...
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2answers
246 views

Is goto to improve DRY-ness OK? [duplicate]

My code has many checks to detect errors in various cases (many conditions would result in the same error), inside a function returning an error struct. Instead of looking like this: err_struct ...
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656 views

Implementing a simple controller in embedded C

Is there a known method or pattern to implement a simple controller for an MVC design in pure C or the switch case approach is the standard? Background : I have an embedded application and I'm ...
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1answer
368 views

Are there theoretical reasons why arrays in C take less RAM than Java?

My experience is that Java requires about twice as much RAM compared to C (comparing char arrays or other comparisons). I also read in a hardware book that Java takes about twice RAM than C. Is is ...
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1answer
152 views

Should I implement a function or a method?

Once in a while I encounter a C function in my colleagues' code. Mostly it is in some helpful objective categories, and those functions are mostly an internal calculation of something or a ...
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comparison of floating point numbers vs. comparsion of Integers in C [closed]

Does comparison of floating point numbers takes (considerably) longer time than comparison of Integers in C? I just wrote a C program of heap sort to sort floating point numbers. I am on ubuntu 14....
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254 views

What is this programming style? “Monoid-ic”?

In a moderately old blog post, Conal Elliot makes an interesting (if less than serious) argument that C is a purely functional language, by drawing a parallel between the combination of the C ...
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505 views

Choice between 1-dimensional and 2-dimensional array

I'm implementing the Chessboard class to represent the chessboard. I've to implement the transformations (reflections and rotations) on the chess board possible. The possible transformations includes ...
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1k views

Better design for a generic doubly linked list around which I plan to make different wrappers?

I am currently writing a C code for a doubly linked list(dll) around which I want to write wrapers for implementing stack, queues etc. instead of writing separate codes for all of them. I'll be ...
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235 views

Simple C: How do I scan this information in properly?

OK this is a simple question but for some reason I just can't get it right. I have to scan from a file hundreds of lines of code and store it in a array (which I can normally do a ok job with) however ...
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1answer
46 views

Need info on malloc trace

When I try the below code I am not clearly able to analyze malloc api internal calls.What I am not clear is about the system call mmap is called only once for 2 or more malloc calls.If I am assigning ...
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1answer
156 views

Unit testing C code?

I learnt about the check testing framework today that seems good. This far I've scripted tests that uses valgrind so that the tests both display output from the tests and from valgrind. Is there a ...
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70 views

Using GPLed headers in LGPLed library

For a specific device there exists a Linux kernel module. This module only initialized the device and provides control mechanisms to user land via ioctls and mmap. To use this the device properly one ...
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168 views

In C, are large 'pointer chains' bad for performance or code cleanliness?

The following for example: i = readString(&packet->data.play_server.updatesign.line1, pbuf, ps); It has a large amount of nested structs/unions. Is this generally frowned upon in code ...
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150 views

Will issues arise packaging libc and pthread with your C apps?

The issue I hit, is that I am packaging shared libraries with my code in order to load GNUTLS, except for libc, because I figured any system will have it. Most of them don't have the required 2.14 for ...
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705 views

Given a number X, how do I find from an array of numbers, a unique combination that adds up to X and has the lowest sum of squares?

Given the number 15 and the array [1, 2, 3, 4, 5, 6] Possible combinations (sum=15) would be: [1, 2, 3, 4, 5] [2, 3, 4, 6] [1, 3, 5, 6] [4, 5, 6] Their respective sum of squares would be: 55, 65, 71 ...
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1k views

Infinite while loop CPU usage

I'm coding an script in C, which is going to check constantly an array of events, the idea is to check if the Date and time of certain event is equal to de current time and trigger something, i'm ...
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2k views

Reconstructing a huffman tree using minimal information in the header

I'm writing a huffman encoding program in C. I'm trying to include the least amount of information in the header as possible, I know the simplest way to decompress the file in the header would be to ...
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158 views

Understanding Arithmetic In C

I have an embarrassingly simple question, but I need to make sure I understand this correctly. I have a *.c file with the following line: CSRConstant = 2*macroParticleCharge*particleCharge/pow(3*...
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Question about moving to embedded systems [closed]

I currently work as a .net developer and have coming up to 3 years experience in the industry as well as a degree in computer science specifically software engineering (I know that means nothing but ...
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4answers
3k views

Help with learning the C++ Qt Framework [closed]

I've been a longtime PHP web developer. But now I've reached the limits and web doesn't fascinate me anymore. I am interested in learning cross-platform development. I have learned Java for almost a ...
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1answer
2k views

Why nginx's http parser doesnt use regular expressions?

I see the http parser written by Igor Sysoev for nginx does not use regular expressions https://github.com/joyent/http-parser What could be the main reason for such design decision? I guess I could ...
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291 views

Violation of the C definition?

The C standard states that any character in the machine's standard printing set will never be negative.But the following code: char c=1234; printf("%d\t%c",c,c); gives a negative output and prints ...
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316 views

Need some advice and feedback on my code's design

I am looking for feedback on the design of my program. I have a shell script call function.sh that defines a lot of helper functions. My intent is to use those bash functions defined in functions.sh ...
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1answer
315 views

Synchronously write file

I am implementing a server in C for a course project. The server should serve more than one client simultaneously. The description of the project states that fork() should be used to serve more than ...
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328 views

Use of c89 in GNU software

In GNU coding standard it is said that free software developer should use C89 because C99 is not widespread yet. 1999 Standard C is not widespread yet, so please do not require its features in ...
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332 views

Materials on structural languages design? [closed]

There is plenty of material about designing software for object oriented programming. Do you know of any good materials for pure structural programming? I am working purely in C and while I can use ...
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56 views

One C codebase as an standalone application as well as Fast-CGI and Apache module

I'm familiar with C, but haven't written any medium or large application in it. I have a requirement to built an application that can be run as a standalone console application as well as Fast-CGI and ...
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1answer
185 views

Data structure to use for time-optimized line-vs-grid check?

I am asking here because I feel that this question can be filed under the "algorithm and data structure concepts" category. Background: I have been recently assigned the task to design and develop a ...
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88 views

What should JITed bytecode do exactly?

I'm working on a VM (and a scripting language for it) that I plan to implement JITing for. I'm only working on the "plumbing" of it now, but I don't want the JIT compiler to be an afterthought. ...
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161 views

Complex iterators in C

note: this was originally asked on SO. Part of my current project involves iterating over sequences that don't necessarily exist. For example, I have something similar to a relational database in ...
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3answers
267 views

How to abide the “allocate in caller” rule when the size is computed in the callee?

Let's say we have an opaque type handle_t that is managed through a simple interface with functions such as: handle_t *handle_init(void); int handle_do(handle_t *); void handle_free(handle_t *); ...
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1answer
264 views

How to check the space complexity of this program?

I have written my version of strstr function in c. I am using a temporary array of size 26. Then is the space complexity O(1) or O(n)? This is my code : void strcheck(char t[], int n, char p[], int ...
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225 views

Memory read/write access efficiency

I've heard conflicting information from different sources, and I'm not really sure which one to believe. As such, I'll post what I understand and ask for corrections. Let's say I want to use a 2D ...
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Parsing mathematical expressions with two values that have parentheses and minus signs

I'm trying to parse equations like the ones below, which only have two values or the square root of a certain value, from a text file: 100+100 -100-100 -(100)+(-100) sqrt(100) by the minus signs,...