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

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16
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10answers
17k views

Why would I learn C++11, having known C and C++?

I am a programmer in C and C++, although I don't stick to either language and write a mixture of the two. Sometimes having code in classes, possibly with operator overloading, or templates and the oh ...
0
votes
0answers
7 views

Defining property and find substitution for copy function of python in cython

I want to cythonize a code in python to speed up the code. In the following you can see my attempt to make my python class understandable for cython: import numpy as np cimport numpy as np ctypedef ...
14
votes
13answers
3k views

Why do operating systems do low level stuff in C and C++? Why not just C++?

On the Wikipedia page for Windows, it states the Windows is written in Assembly for the bootloader and task switcher, and C and C++ for kernel routines. IIRC, you can call C++ functions from an ...
9
votes
4answers
951 views

Pointer indexing

I am currently reading a book titled "Numerical Recipes in C". In this book, the author details how certain algorithms inherently work better if we had indices starting with 1 (I don't entirely follow ...
-7
votes
0answers
97 views

SOLVED! Error in result: 5^2 = 24 and 10^2 = 99? [on hold]

The compiler is GCC and the program Codelite. Using double or float works!
-5
votes
0answers
55 views

How to become malware analyst [on hold]

I am willing to be a malware analyst. I am 17 years old and want to be guided. I tried learning x86 assembly form (the art of assembly) but it was complex and I believe that it is very old (I don't ...
4
votes
6answers
6k views

When is C a better choice than C++? [closed]

I can't imagine that there's any reason not to use the OOP features of C++. It's is just as fast as C, and - what's more important to me - it's transparent, just as C. (I mean "transparent" that I ...
-1
votes
0answers
141 views

Picking a language for writing code [on hold]

I'm in a situation, which I guess would've been encountered by all professional programmers at some point. For the same of rapid development, I chose to write modules in python. Soon, in our perf ...
0
votes
0answers
40 views

How does the android JNI work [closed]

I am currently trying to create an iPhone/android app I have chosen to write the model of my program in C++ since it is supported by both platforms. I have been able to compile my C++ source into the ...
-2
votes
1answer
95 views

How can we make a certain thing inbuilt in c language with our own header file?

I want to make the basic trigonometric functions in maths inbuilt functions using my own header file . so as the users can do trigonometry in c language compilers.
2
votes
3answers
269 views

Understanding how variable assignment works

When I started learning C programming a few years ago, my tutor taught me similar to most of the tutors around the world. She said me the very basic things like any int datatype is of 2 bytes memory. ...
1
vote
4answers
570 views

Why would a C executable be smaller when compared to C++ executable

I'm trying to understand why the output file sizes are significantly different when using a C and a C++ compiler. I was writing a small hello world program in C and C++, I noticed that in C version, ...
2
votes
0answers
148 views

What's wrong with this pointer? [migrated]

I though I had finally understood pointers but then I encountered this issue: typedef struct { unsigned int a; unsigned int b; } Bar; Bar *foo; foo->a = 3; This last instruction ...
2
votes
4answers
1k views

C/C++: Who uses the logical operator macros from iso646.h and why? [closed]

There has been some debate at work about using the merits of using the alternative spellings for C/C++ logical operators in iso646.h: and && and_eq &= bitand & bitor ...
16
votes
4answers
516 views

How bad is it calling println() often than concatenating strings together and calling it once?

I know output to the console is a costly operation. In the interest of code readability sometimes it is nice to call a function to output text twice, rather than having a long string of text as an ...
1
vote
2answers
66 views

How to handle enums in an indirection with functionpointers at ANSI-C?

Moinsen, I am somehow stucked in a design problem. Language is ANSI-C. Lets assume we have a tinkerbox of software-modules: one module for the logic Logic (at least) one module doing some logging ...
-5
votes
0answers
27 views

Using Eclipse CDT tools for C/C++ — How to use interactive runtime for programs? [closed]

For the code below, I had expected it to go line by line but the output received is all at a time i.e, when I run it after building I pass ib the input in the first line and receive result next to it ...
-2
votes
4answers
198 views

Benefits of porting C library to C++ [closed]

Say we take any C library such as libpng or libvorbis and convert it so that it compiles as C++ (only the minimum changes to make it compile as C++ code). Can the compiler do extra optimizations when ...
2
votes
4answers
1k views

Going through The C Programming Language K&R in Visual Studio

From what I have read, K&R seems to be a good place to start learning programming in general, and C programming specifically. However, I've just started the first chapter and I have a few ...
-1
votes
1answer
104 views

Programmer Analyst vs Software Engineer [closed]

So I've heard the job title "programmer analyst" and "business analyst" thrown around for software jobs recently. How do the responsibilities of Programmer Analysts, Business Analysts and Software ...
6
votes
1answer
213 views

Suggested method for extracting a standalone C library from an existing R package?

My group has been developing an R package to simulate plant growth (see GitHub repository). The R package uses .Call to interface with C. We have decided that it would be worthwhile to create a ...
0
votes
3answers
127 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 ; ...
-2
votes
0answers
71 views

How can I improve the following code in terms of faster execution? [migrated]

The problem is described here - Aaah!. My source code for the problem is below. I one of the fast running codes, but not the best. What changes can I make so as to improve the efficiency of the code. ...
0
votes
0answers
4 views

What happens when there is multiple expressions in the condition part of a for loop seperated by commas? [migrated]

I have an infinite loop here, but why? int end = 5; for(int i = 0; i < end, printf("at condition i=%d\n",i); ++i) { printf("inside i=%d\n",i); }
0
votes
0answers
74 views

Different ways of addressing pointers C/C++ [migrated]

I'm a little confused about accessing specific addresses using c style pointers. I have a 32 bit chip which I'm tryin to program. I need to flip some bits or whatever in ram. The following solution ...
2
votes
3answers
234 views

Transitioning from Java & C to C++

I learned Java and I'm pretty competent programming in it. I also learned C recently. I looked at a comparison between Java and C++ and I like C++'s features like operator overloading and its speed. ...
1
vote
2answers
143 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 = ...
9
votes
2answers
581 views

Why can't arrays be passed as function arguments in C?

Following this comment, I've tried to google why, but my google-fu failed. Comment from link: [...] But the important thing is that arrays and pointers are different things in C. Assuming ...
0
votes
3answers
139 views

Use of malloc in C

Is it necessary to call free function every time we use malloc in C. I am asking this because I have seen many times that it is not called . Thank you
2
votes
1answer
47 views

gcc -S seems a bit misshapen with shifting and ANDing bits

Example: int c = 4; int p = 5; if (p & (1 << c)) printf("ok\n"); else printf("nop\n"); gcc -S: movl -4(%rbp), %eax /* eax holds the variable c */ movl -8(%rbp), %edx /* ...
55
votes
10answers
6k views

Why do C arrays not keep track of their length?

What was the reasoning behind not explicitly storing an array's length with an array in C? The way I see it, there are overwhelming reasons to do so but not very many in support of the standard ...
0
votes
0answers
65 views

Parsing mathematical experssions 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 ...
1
vote
1answer
73 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 ...
0
votes
2answers
266 views

Is there a better way to organize my module tests that avoids an explosion of new source files?

I've got a neat (so I thought) way of having each of my modules produce a unit-test executable if compiled with the -DTESTMODULE flag. This flag guards a main() function that can access all static ...
0
votes
2answers
247 views

Why is it called a memory leak?

I am a hobbyist programmer, bit of a stickler for terminology, currently learning C and recently came across the concept of Memory Leak. Now, I do understand what it means. Dynamic memory allocated to ...
1
vote
1answer
100 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 ...
7
votes
2answers
996 views

Questions about linking libraries in C

I am learning C (still very much a beginner) on Linux using the GCC compiler. I have noticed that some libraries, such as the library used with the math.h header, need to be linked in manually when ...
0
votes
1answer
93 views

Global variable in a Linux shared library

Suppose we have the following setup under Linux, .so library named "libcnt.so" and 3 user space apps: "app1", "app2", "app3". This library does 1 simple thing, it says to the app (app dynamically ...
3
votes
3answers
155 views

Organization of DLL linked functions

This is a code organization question. I got my basic code working but when I expand it, it will be terrible. I have a DLL which I don't have a .lib for. Therefore I have to use the whole ...
4
votes
1answer
247 views

Why is the function called lseek(), not seek()?

The C function for seeking in a file is called lseek(). Why ins't it called just seek()?
1
vote
1answer
183 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 ...
2
votes
3answers
160 views

Why are there two different kinds of linking, i.e. static and dynamic?

I've been bitten for the n-th time now by a library mismatch between a build and deployment environment. The build environment had libruby.so.2.0 and the deployment environment had libruby.a. One ruby ...
49
votes
11answers
13k views

Why has C prevailed over Pascal?

My understanding is that in the 1980s, and perhaps in the 1990s too, Pascal and C were pretty much head-to-head as production languages. Is the ultimate demise of Pascal only due to Borland's neglect ...
15
votes
8answers
2k views

Why does Clang/LLVM warn me about using default in a switch statement where all enumerated cases are covered?

Consider the following enum and switch statement: typedef enum { MaskValueUno, MaskValueDos } testingMask; void myFunction(testingMask theMask) { switch theMask { case ...
4
votes
1answer
534 views

Why are most GNU's software written in C [closed]

I am a Java developer, and I rarely write GUI program in C. However, I noticed that many GNU's projects, such as PSPP, R, Dia, etc., are written in C, instead of Java or C++. I personally don't mind ...
0
votes
3answers
144 views

How can I handle this string concatenation in C in a reusable way

I've been writing a small C application that operates on files, and I've found that I have been copy+pasting this code around my functions: char fullpath[PATH_MAX]; fullpath[0] = '\0'; ...
0
votes
2answers
72 views

Looking for a certain datatype if it exists

I'm looking for the kind of a certain datatypes. The main idea of this datatype is to describe a productionline containing several steps. Each step should be represented as a "vertex" containing an ...
1
vote
4answers
644 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 ...
1
vote
2answers
304 views

“bug” in C++11 text by Stroustrup?

I found an apparent contradiction in the c++ text having to do with the result of the c_str() function operating on std:strings (in my copy, the definition and contradiction are on p1040). First it ...
4
votes
6answers
2k views

sizeof style: sizeof(type) or sizeof variable?

I've seen two styles of using sizeof for memory-related operations (such as in memset or malloc): sizeof(type), and sizeof variable or sizeof(variable) Which one would you prefer, or would you use ...