C

Great Reads

by Martin Mitáš

How to support scrolling within your controls.

Synchronization with Visual C++ and the Windows API

by Espen Harlinn

Choosing the right synchronization mechanisms when working with threads, thread-pools, and I/O Completion ports to create high performance asynchronous servers in C++

Intermediate Data Clustering with k-means

by Andy Allinger

Add features to k-means for missing data, mixed data, and choosing the number of clusters

Authenticated Encryption

by Jeffrey Walton

Perform authenticated encryption with Crypto++.

Latest Articles

BASIC is not dead! Neither is the WIN32! Time to end the myth. (Part 3)

by Chris Boss

BASIC: A powerful language often underestimated and undervalued

RGFW | Singler-Header Lightweight Framework for Basic Window and Graphics Context Handling (like GLFW)

by ColleagueRiley

A multi-platform single-header very simple-to-use framework library for creating GUI Libraries or simple GUI programs.

How to Design an AXI4 Stream Interface in Vitis HLS

by FPGANinja

A walkthrough and source code for designing a stream interface in Vitis HLS

Fast SSE Pseudo Random Number Generator

by Alexey Shtykov

The thing that could generate pseudo random numbers faster than standard library does

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C

I recently started coding with C, while using strlen function I get the exact number of length of string and sometimes not

N 30 Apr 2024 by merano99

First of all, fgets() expects the maximum buffer size and not the length of an uninitialized string as already read in answer 1. When asked why the result is 4 and not 3, it should be noted that fgets() also reads the end-of-line character. When...

I recently started coding with C, while using strlen function I get the exact number of length of string and sometimes not

U 30 Apr 2024 by Dhanush G

#include #include int main() { char a[100]; printf("enter name:"); fgets(a,strlen(a),stdin); printf("%d",strlen(a)); } output: enter name:abc 4 What I have tried: shouldn't the lenght be 3 instead of 4?

I recently started coding with C, while using strlen function I get the exact number of length of string and sometimes not

U 30 Apr 2024 by Richard MacCutchan

char a[100]; printf("enter name:"); fgets(a,strlen(a),stdin); // at this point a contains any random set of characters You are calling strlen on an unitialised array, so the result will be anything from zero to the largest integer value. A...

How do I obtain a list of window users only.

N 30 Apr 2024 by Richard Deeming

Assuming you're trying to replicate the list shown on the Windows lock screen, it's not as simple as passing a filter to the list. By default, Windows will show all enabled local user accounts on the lock screen, assuming the computer is not...

programming

How do I obtain a list of window users only.

N 30 Apr 2024 by Dave Kreskowiak

There is no procedure for filtering the users based on what you don't recognize. User accounts are user accounts. In a corporate domain environment, you can have other users you don't recognize, but you don't have any way of filtering them out...

programming

Create a C program that entitled "BBQ MANAGEMENT SYSTEM in C".BBQ MANAGEMENT include menu, sales report and exit

N 30 Apr 2024 by Pete O'Hanlon

Well, whoever set you this piece of homework didn't give you a lot to go on. We aren't going to give you much to go on either because this is not a site where people will write code for you. If you bring code along that's not working, we're more...

How do I obtain a list of window users only.

U 29 Apr 2024 by samtoad

I'm again attempting to obtain a list of all users on a windows platform. I already obtained a general user list using the netuserenum function. I think you do the same with other functions, like NetQueryDisplayInformation. But my question...

programming

How to overcome this: the system detected an overrun of a stack-based buffer.

U 29 Apr 2024 by k5054

Without some code examples, it's not clear where the issue is. In particular, how are you getting your data? For example char buff[10]; scanf("%s", buff); will overflow your input buffer. You can tell scanf how long your input buffer is...

programming

How to overcome this: the system detected an overrun of a stack-based buffer.

N 29 Apr 2024 by Rick York

When I must use fixed-sized text buffers I make sure to use the size-limited library functions since they are much safer. Here is an example with your data : #define DATE_LENGTH 11 typedef char DateStr[ DATE_LENGTH + 1 ]; // plus one for the...

programming

How to overcome this: the system detected an overrun of a stack-based buffer.

N 29 Apr 2024 by samtoad

In an application that I'm working on, I use dates, with size of the 'char' being declared as datestr[12], with the max length of 11 -> thru out the whole program... While testing all possible situations, I entered a date greater than size of 11...

programming

How to use strncpy correctly?

U 27 Apr 2024 by Member 16250016

Hello, i try simple test function string in c, #include #include #include #include int main(int argc, char **argv) { const char *str ="G06111412/031/PL05"; unsigned short maxLen = strlen( str );...

How to use strncpy correctly?

N 26 Apr 2024 by OriginalGriff

Nothing there is saying that the substring is invalid: you get what I would expect. If I run your code at onlinegdb.com, I get a different result (if I ignore the copious compiler warnings): string "G06111412/031/PL05"- has lenght 18 char, cut...

Can anyone help my flowchart? I have trouble solving my flowchart

N 25 Apr 2024 by merano99

The work description is either very incomplete and some things don't seem to fit together properly. The current description contains the following: Title:BBQ MANAGEMENT SYSTEM IN C My professor told me to put Menu: including drinks, foods and...

Can anyone help my flowchart? I have trouble solving my flowchart

N 24 Apr 2024 by Pete O'Hanlon

Let's talk about what the question is really asking you for, and why your question is impossible to answer as it currently reads. To go back to basics, a flowchart is a series of steps showing that you can break a "big" problem into small,...

Can anyone help my flowchart? I have trouble solving my flowchart

N 24 Apr 2024 by inday badiday

Title:BBQ MANAGEMENT SYSTEM IN C My professor told me to put Menu: including drinks, foods and etc. Sales Report Exit What I have tried: I am trying to solve the problem but I really can't

Why float display wrong in C

U 24 Apr 2024 by Member 16250016

Hello, i try simple test data type float in c, float can represent a range between 10^-37 to 10^ 37, but exemple follow show wrong value when runtime. #include #include #include #include int main(int...

Why float display wrong in C

N 23 Apr 2024 by CPallini

What Every Computer Scientist Should Know About Floating-Point Arithmetic[^]

Why float display wrong in C

N 23 Apr 2024 by OriginalGriff

To add to what k5054 has said, computers don't actually know about floating point numbers, they work in whole bytes and a float in C is stored in a relatively small amount of memory: 4 bytes (or 32 bits) only. This is broken into the mantissa...

Why float display wrong in C

N 23 Apr 2024 by k5054

A float has only about 7 decimal digits of precision. So for example given #include int main() { float f1 = 3445678336.0; float f2 = 3445678337.0; float result = f2 - f1; printf("%f\n", result); } The result is not...

How to read a delimited text file and load the data into arrays in C++

N 23 Apr 2024 by k5054

Take a look at std::basic_istream::operator>> - cppreference.com[^] Look at the example code, which shows you how to read a value from a file into a variable. This assumes that your data (#1, #2, #3 etc) are all normally formatted...

How to read a delimited text file and load the data into arrays in C++

N 23 Apr 2024 by CPallini

Try #include #include #include #include using namespace std; using Row = array; int main() { vector v; ifstream ifs("cmb.txt"); if (ifs) { string line; getline(ifs,...

How to read a delimited text file and load the data into arrays in C++

U 23 Apr 2024 by juliet6

Hello, I am stuck trying to convert a delimited text file with five columns of data structured like this: col1 col2 col3 col4 col5 #1 #1 #1 #1 #1 #2 #2 #2 #2 #2 #3 #3 #3 #3 #3 ... I can print out each line of the...

What is the error of this mergesort C programming?

16 Apr 2024 by Rick York

One error is apparent - this line in the main function : void mergesort(a,0,n-1); should not have the void statement in it. It should be like this : mergesort(a,0,n-1); Another one I noticed is also in main : printf( "%d", &a[i]...

What is the error of this mergesort C programming?

16 Apr 2024 by OriginalGriff

Toi add to what Rick has said, you should expect to get syntax errors every day, probably many times a day while you are coding - we all do regardless of how much experience we have! Sometimes, we misspell a variable, or a keyword; sometimes we...

What is the error of this mergesort C programming?

16 Apr 2024 by Rajesh Majumder from Durham

What is the error of this mergesort C programming? What I have tried: #include void mergesort(); void merge(); main(){ int a[40],i,n; printf("Enter Array Size-"); scanf("%d",&n); printf("Enter Array Elements-"); for(i=0;i

Gcc issues incompatible pointer types warning

9 Apr 2024 by merano99

Karsten has already addressed the problem of unsafe data types that are also accessed globally. Global variables and the limitation of a pointer field should be avoided. Especially if the code is to be used flexibly by other developers with as...

Gcc issues incompatible pointer types warning

8 Apr 2024 by KarstenK

I dont like your code at all. The mismatch of types is problematic. Also the use of global data leeds to bugs when your code may evolve. tips: - store data in some byte array and give the save function also the size of data, so it can memcpy the...

Gcc issues incompatible pointer types warning

8 Apr 2024 by steveb

int main() { int n = 10; float f = 10.5; save((void*) & n); save((void*)&f); int* pn; retrieve(0, (void**)&pn); printf("%d\n", *pn); float* pf; retrieve(1, (void**)&pf); printf("%g\n", *pf); return 0; }

Gcc issues incompatible pointer types warning

8 Apr 2024 by ilostmyid2

In C, I need a function to return a void * via one of its arguments. Assume that there's a database which holds pointers to any type of data. Once the user stores the pointers and in other parts of the program the pointers are required to be...

C code for implementing a feedback loop to modify an initial argument?

1 Apr 2024 by KarstenK

Try some Learn C tutorial. Learn the basics before you start attempting to write some code. Tip: learn to use the debugger.

C code for implementing a feedback loop to modify an initial argument?

1 Apr 2024 by Pete O'Hanlon

We don't usually give people code if they haven't actually attempted anything yet. We will help you if you get stuck with your code, but we won't write it for you. What I will do, is offer you some guidance as to how to solve this. Write a...

C code for implementing a feedback loop to modify an initial argument?

1 Apr 2024 by Intellijoule

I want to implement a classical servo-like loop equation. For example, if A is gain, then: Af=A/(1-b*A), where Af is the resulting feedback gain, and B is beta, the sampled portion that must be updated to maintain a set point output of the loop's...

How to implement smooth car movement and turns on a grid in a C game

1 Apr 2024 by KarstenK

As somebody already wrote: best is to hold the complete map (your background) as drawable image the whole game, so your drawing code may look similar like:void drawScreen(int x, int y) { if( isSomeCarAt( x, y ) { drawCar( x, y ); } else {...

How to implement smooth car movement and turns on a grid in a C game

31 Mar 2024 by steveb

Generally in a computer graphics smooth rendering is achieved by using a back buffer to which an image is drawn with subsequent BLIT (Block Image Transfer) into the Video memory. Drawing into the video memory directly results in visual anomalies...

How to implement smooth car movement and turns on a grid in a C game

30 Mar 2024 by merano99

To restore the background position, the old background can be saved with its position before it is overwritten by cars or players. As soon as the field is free again, the saved position can be restored. An alternative would be to use a copy of...

How to implement smooth car movement and turns on a grid in a C game

30 Mar 2024 by k5054

If I were doing this, I might be tempted to track the grid, the player and the car(s) separately, something like: struct position { int row, col }; struct position player; struct vehicle { char direction; struct position pos; }; // and...

How to implement smooth car movement and turns on a grid in a C game

30 Mar 2024 by DosNecro

/* Rasal Amarasurya */ /* 21304178 */ #include #include #include /* For malloc, free */ #include "game.h" /* Include the game header */ void initializeGame(char **grid, int rows, int cols, FILE *file, int...

Unexpected game exit upon player movement in C ncurses game

29 Mar 2024 by DosNecro

Unexpected game exit upon player movement in C ncurses game

29 Mar 2024 by merano99

CPallini is right! The comment in the source code says that the initializeGame() function should determine the player position. int playerRow, playerCol; /* Removed the initialization here as it's set in initializeGame */ However, the prototype...

Adding a function to a DLL file.

28 Mar 2024 by KarstenK

Verify that your new dll function has the same export macro signature as the other dll function. Mostly some DLL_EXPORT or similar macro stuff. Another common issue is that, your new dll isnt used by the calling program but a stale version in...

WinAPI

programming

Unexpected game exit upon player movement in C ncurses game

28 Mar 2024 by CPallini

You failed to properly initialize playerRow, playerRow variables. Put a breakpoint at movePlayer function in order to see that live.

Adding a function to a DLL file.

27 Mar 2024 by Rick York

Firstly, there are no limits to DLL sizes or capacities. Secondly, it is important to note what is emitting that error message. It could be the compiler or the linker. If it is from the compiler then you have not defined a prototype for the...

WinAPI

programming

Adding a function to a DLL file.

27 Mar 2024 by samtoad

Currently, I'm trying to add another "C" routine into a DLL file. I've made the routine inside a DLL source file. I've declared the routine, and also indicated the intentions as it will be exported. The function name is also included in a DEF...

WinAPI

programming

Seeking feedback: OSTEP chapter 6 measurement homework

24 Mar 2024 by Sean Cundiff

Are you intending for only the parent child process to have CPU affinity? if(sched_setaffinity(0, sizeof(mask), &mask) == -1) { perror("sched_setaffinity()"); return EXIT_FAILURE; } If not you should probably change...

Linux

How can I write correct code to solve the equation in C

24 Mar 2024 by merano99

In fact, a lot can go wrong here at the same time, as Rick has already written. In addition to the problem of choosing the correct search range and step size, the function also has 4 jumps, as the formula already reveals. In addition to the risk...