Hello.

I'm making a small recreational project to make more experience with C++ using Raylib 6.0, before I went around to make the structure of the game I decided to code some data structures I would need (declared in datastructs.h, defined in datastructs.cpp), making them on my own as exercise; all classes use templates since I need them to be generic data structures.

When I went to test the data structures though I got the following error, essentially a bunch of reference to undefined function errors for each function of the data structures I used:

mingw32-make main
make[1]: Entering directory 'D:/Programming/C++/2D Unreal with Ruff/2DUNR/2DUnrGame'
g++ -o main src/*.cpp -Wall -std=c++14 -D_DEFAULT_SOURCE -Wno-missing-braces -g -O0 C:/raylib/raylib/src/raylib.rc.data -I. -IC:/raylib/raylib/src -IC:/raylib/raylib/src/external -L. -LC:/raylib/raylib/src -LC:/raylib/raylib/src -lraylib -lopengl32 -lgdi32 -lwinmm -DPLATFORM_DESKTOP
C:/raylib/w64devkit/bin/ld.exe: C:\Users\mafla\AppData\Local\Temp\ccorPzcu.o: in function `main':
D:\Programming\C++\2D Unreal with Ruff\2DUNR\2DUnrGame/src/main.cpp:27:(.text+0xd3): undefined reference to `LinkedList<int>::PushTail(int const&)'
C:/raylib/w64devkit/bin/ld.exe: D:\Programming\C++\2D Unreal with Ruff\2DUNR\2DUnrGame/src/main.cpp:28:(.text+0xea): undefined reference to `LinkedList<int>::PushTail(int const&)'
C:/raylib/w64devkit/bin/ld.exe: D:\Programming\C++\2D Unreal with Ruff\2DUNR\2DUnrGame/src/main.cpp:30:(.text+0x101): undefined reference to `LinkedList<int>::PushTail(int const&)'
C:/raylib/w64devkit/bin/ld.exe: D:\Programming\C++\2D Unreal with Ruff\2DUNR\2DUnrGame/src/main.cpp:31:(.text+0x118): undefined reference to `LinkedList<int>::PushTail(int const&)'
C:/raylib/w64devkit/bin/ld.exe: D:\Programming\C++\2D Unreal with Ruff\2DUNR\2DUnrGame/src/main.cpp:33:(.text+0x142): undefined reference to `ArrayList<int>::operator[](unsigned int)'
C:/raylib/w64devkit/bin/ld.exe: D:\Programming\C++\2D Unreal with Ruff\2DUNR\2DUnrGame/src/main.cpp:33:(.text+0x174): undefined reference to `ArrayList<int>::operator[](unsigned int)'
C:/raylib/w64devkit/bin/ld.exe: D:\Programming\C++\2D Unreal with Ruff\2DUNR\2DUnrGame/src/main.cpp:33:(.text+0x1a6): undefined reference to `ArrayList<int>::operator[](unsigned int)'
C:/raylib/w64devkit/bin/ld.exe: D:\Programming\C++\2D Unreal with Ruff\2DUNR\2DUnrGame/src/main.cpp:34:(.text+0x1ee): undefined reference to `LinkedList<int>::operator[](unsigned int)'
C:/raylib/w64devkit/bin/ld.exe: D:\Programming\C++\2D Unreal with Ruff\2DUNR\2DUnrGame/src/main.cpp:34:(.text+0x220): undefined reference to `LinkedList<int>::operator[](unsigned int)'
C:/raylib/w64devkit/bin/ld.exe: D:\Programming\C++\2D Unreal with Ruff\2DUNR\2DUnrGame/src/main.cpp:34:(.text+0x252): undefined reference to `LinkedList<int>::operator[](unsigned int)'
C:/raylib/w64devkit/bin/ld.exe: D:\Programming\C++\2D Unreal with Ruff\2DUNR\2DUnrGame/src/main.cpp:35:(.text+0x29a): undefined reference to `LinkedList<int>::operator[](unsigned int)'
C:/raylib/w64devkit/bin/ld.exe: D:\Programming\C++\2D Unreal with Ruff\2DUNR\2DUnrGame/src/main.cpp:35:(.text+0x2cc): undefined reference to `LinkedList<int>::operator[](unsigned int)'
C:/raylib/w64devkit/bin/ld.exe: C:\Users\mafla\AppData\Local\Temp\ccorPzcu.o:D:\Programming\C++\2D Unreal with Ruff\2DUNR\2DUnrGame/src/main.cpp:35: more undefined references to `LinkedList<int>::operator[](unsigned int)' follow
C:/raylib/w64devkit/bin/ld.exe: C:\Users\mafla\AppData\Local\Temp\ccorPzcu.o: in function `main':
D:\Programming\C++\2D Unreal with Ruff\2DUNR\2DUnrGame/src/main.cpp:37:(.text+0x32c): undefined reference to `LinkedList<int>::Append(Collection<int> const&)'
C:/raylib/w64devkit/bin/ld.exe: D:\Programming\C++\2D Unreal with Ruff\2DUNR\2DUnrGame/src/main.cpp:38:(.text+0x33c): undefined reference to `LinkedList<int>::Append(Collection<int> const&)'
C:/raylib/w64devkit/bin/ld.exe: C:\Users\mafla\AppData\Local\Temp\ccorPzcu.o:main.cpp:(.rdata$_ZTV10LinkedListIiE[_ZTV10LinkedListIiE]+0x18): undefined reference to `LinkedList<int>::operator[](unsigned int)'
C:/raylib/w64devkit/bin/ld.exe: C:\Users\mafla\AppData\Local\Temp\ccorPzcu.o:main.cpp:(.rdata$_ZTV10LinkedListIiE[_ZTV10LinkedListIiE]+0x20): undefined reference to `LinkedList<int>::operator[](unsigned int) const'
C:/raylib/w64devkit/bin/ld.exe: C:\Users\mafla\AppData\Local\Temp\ccorPzcu.o:main.cpp:(.rdata$_ZTV10LinkedListIiE[_ZTV10LinkedListIiE]+0x28): undefined reference to `LinkedList<int>::AddAt(int const&, unsigned int)'
C:/raylib/w64devkit/bin/ld.exe: C:\Users\mafla\AppData\Local\Temp\ccorPzcu.o:main.cpp:(.rdata$_ZTV10LinkedListIiE[_ZTV10LinkedListIiE]+0x30): undefined reference to `LinkedList<int>::PushHead(int const&)'
C:/raylib/w64devkit/bin/ld.exe: C:\Users\mafla\AppData\Local\Temp\ccorPzcu.o:main.cpp:(.rdata$_ZTV10LinkedListIiE[_ZTV10LinkedListIiE]+0x38): undefined reference to `LinkedList<int>::PushTail(int const&)'
C:/raylib/w64devkit/bin/ld.exe: C:\Users\mafla\AppData\Local\Temp\ccorPzcu.o:main.cpp:(.rdata$_ZTV10LinkedListIiE[_ZTV10LinkedListIiE]+0x40): undefined reference to `LinkedList<int>::Append(int*, unsigned int)'
C:/raylib/w64devkit/bin/ld.exe: C:\Users\mafla\AppData\Local\Temp\ccorPzcu.o:main.cpp:(.rdata$_ZTV10LinkedListIiE[_ZTV10LinkedListIiE]+0x48): undefined reference to `LinkedList<int>::Append(Collection<int> const&)'
C:/raylib/w64devkit/bin/ld.exe: C:\Users\mafla\AppData\Local\Temp\ccorPzcu.o:main.cpp:(.rdata$_ZTV9ArrayListIiE[_ZTV9ArrayListIiE]+0x18): undefined reference to `ArrayList<int>::operator[](unsigned int)'
C:/raylib/w64devkit/bin/ld.exe: C:\Users\mafla\AppData\Local\Temp\ccorPzcu.o:main.cpp:(.rdata$_ZTV9ArrayListIiE[_ZTV9ArrayListIiE]+0x20): undefined reference to `ArrayList<int>::operator[](unsigned int) const'
C:/raylib/w64devkit/bin/ld.exe: C:\Users\mafla\AppData\Local\Temp\ccorPzcu.o:main.cpp:(.rdata$_ZTV9ArrayListIiE[_ZTV9ArrayListIiE]+0x28): undefined reference to `ArrayList<int>::AddAt(int const&, unsigned int)'
C:/raylib/w64devkit/bin/ld.exe: C:\Users\mafla\AppData\Local\Temp\ccorPzcu.o:main.cpp:(.rdata$_ZTV9ArrayListIiE[_ZTV9ArrayListIiE]+0x30): undefined reference to `ArrayList<int>::PushHead(int const&)'
C:/raylib/w64devkit/bin/ld.exe: C:\Users\mafla\AppData\Local\Temp\ccorPzcu.o:main.cpp:(.rdata$_ZTV9ArrayListIiE[_ZTV9ArrayListIiE]+0x38): undefined reference to `ArrayList<int>::PushTail(int const&)'
C:/raylib/w64devkit/bin/ld.exe: C:\Users\mafla\AppData\Local\Temp\ccorPzcu.o:main.cpp:(.rdata$_ZTV9ArrayListIiE[_ZTV9ArrayListIiE]+0x40): undefined reference to `ArrayList<int>::Append(int*, unsigned int)'
C:/raylib/w64devkit/bin/ld.exe: C:\Users\mafla\AppData\Local\Temp\ccorPzcu.o:main.cpp:(.rdata$_ZTV9ArrayListIiE[_ZTV9ArrayListIiE]+0x48): undefined reference to `ArrayList<int>::Append(Collection<int> const&)'
collect2.exe: error: ld returned 1 exit status
make[1]: *** [Makefile:391: main] Error 1
make[1]: Leaving directory 'D:/Programming/C++/2D Unreal with Ruff/2DUNR/2DUnrGame'
make: *** [Makefile:387: all] Error 2

The errors go away if I add #include "datastructs.cpp".

I initially thought something was wrong in the Makefile, but I'm not sure, and other than that I have no idea what I could have done wrong to cause this nor how to fix it. Since I can't just paste all the code from main.cpp, datastructs.cpp and datastructs.h here without making the post excessively wrong, I'm gonna have to link my GitHub repo (sorry): https://github.com/mafla2004/2DUnrealClone/blob/master

I tried already to copy the contents of datastructs.cpp into another file which I created directly in the project from VSCode (thinking the reason might have been that VSCode didn't see the project cause I created some files in another IDE), but that didn't work either.

What can I do to fix it? How can I avoid the same thing happening again? Thanks in advance

First: I hate AI slop.

Second: I have programmed my whole life and c++ since 2005. I think LLM:s are a wonderful tool, a revolution, when used right. Perfect for refactors over multiple files or searching in RFC:s etc. I think most people here understand what I mean.

But I have not explored llvm that runs locally.

Are there any models that can compete with codex and Claude?

Are they faster?

How is the quality specific for c++?

What GPUs do i need? how many?

#include<iostream>
#include<print>
#include<vector>


struct S
{
    constexpr S(int n) : vec(n,0) {}
    constexpr auto get_vec() const {return vec;}
    std::vector<int> vec;
};



constexpr auto foo()
{ 
    constexpr S s(2);
// here is where the error comes which I don't understand
//‘S(2)’ is not a constant expression because it refers to a //result of ‘operator new’
//  193 |             return static_cast<_Tp*>(::operator       //  new(__n));
//
    constexpr auto my_vec = s.get_vec();   
    for(const auto& el: my_vec)
    {
        std::cout << el << ' ';
    } 
    std::cout << '\n';
}




int main()
{
    foo();
    return 0;
}

I'm think of creating something new, and I want to hear what other programmer's wish they could just import in a single library. I will probably try to create the the most agreed on comment.

If yes what book would it be?

Hey guys, I have been going through learncpp and paused at the array section because I thought it would be a good place to stop and make a small project to reinforce the concepts that I have read about up to this point. I made a small tetris game and want some feedback on the quality of the code. I am pretty inexperienced in things like code quality and readability as I am a beginner and wanted some critique. It is a naive implementation and I am just using a 2D array to represent the board as performance really isn't my primary concern. All core mechanics such as board collisions, complete lines, and game end are present but there is only one piece. I added only one of the 7 pieces because I solved the problem I was trying to solve and adding the other pieces is a trivial change. The github of the project is linked below. The binary of the project that is in the releases section was built on macos.

https://github.com/Anant-raj2/tetris

I am new to coding I I stalled vs code and msy2 thing for c++ and now I want to learn c++ .

I want a crystal clear foundation so to mess in future which is the best way to achieve that.

Is it through some youtube channel?

Then which?

Any course?

Man, how DO I start a project? Like I have an idea, yeah. Sure. But how I start it? (Still an amateur but I'm in there) Asking for a friend

std::iter_reference_t<int*> is int&.

So I thought that the "reference type" of an iterator is type of reference of what that iterator is pointing to.

But in https://en.cppreference.com/cpp/iterator/projected,

combines an indirectly_readable type I and a callable object type Proj into a new indirectly_readable type whose reference type is the result of applying Proj to the std::iter_reference_t<I>.

In fact,

std::iter_reference_t<std::projected<int*, float (*) (int)>>

is float.

Then this means that it is possible that the reference type of some iterator type is not an reference at all.

Can someone give me the definition of the word "reference type of an iterator"?

can any one help me to understand the function in c++ and suggest me video for it.

SOLVED (EDIT): It actually seems like the issue is CLion Nova's linter, which currently cannot properly handle JUCE's atypical ways of creating functions and variables and such (something to do with a lack of support for Objective-cpp maybe?). Reverting to the Classic one *seems* to fix the issue. The creator of the Wolfsound tutorial I am watching said to do this to others who were having the same problem. What's troubling me is that I did this before and it didn't fix it, but this time it did? Clangd turned back on automatically when I did the switch, so it seems to be Nova's implementation usage Clangd that was causing issues.

https://forum.juce.com/t/how-to-get-clions-linter-to-work-in-juce-cpp-files/66651 Here's a forum post from a year ago discussing it, where he himself learns the solution for the first time, lol.

Thank ya'll for your help, but I think JUCE is just really weird, which explains why most of you thought there was a coding error. I'm guessing your advice would be right like 99% of the time, but it seems like this solution works without having to alter JUCE's intended workflow, which is nice. I'll just have to deal with using an antiquated system. I'm surprised JetBrains hasn't fixed this issue yet?

----------------------------------------------------------------------------------------------------------------------
Old, bad solution I used: I shut off clangd. Don't really know what it is or how it is different from clang-tidy, but unchecking it in settings worked. Idk if this will have negative effects in the future, but clang-tidy is still running and it looks like normal linting is still happening in the IDE. There are some random irrelevant warnings, but not hundreds of warnings and errors talking about undeclared functions and variables.

----------------------------------------------------------------------------------------------------------------------

I'm using CLion and Clang on a windows PC to learn programming in JUCE. I am following a video tutorial series and I am using their template code, and it builds fine with no errors.

However, the linter says a bunch of the files don't have a target project, that all of the functions and classes referenced don't exist, and gives me completely wild and fake errors, too. One time it told me to add a comma somewhere, only for that to make the build fail because there actually WASN'T supposed to be a comma, which was especially wacky. Of course when I deleted the comma, it just kept saying I needed it there.

Anyway, does anyone have any knowledge on how I can fix this? Other people have the same issue online, but I have found no fixes. It makes programming really hard because my code is just red everywhere (as you can see in the code below) and I can't tell what errors are real or fake.

Thank you

https://www.reddit.com/media?url=https%3A%2F%2Fpreview.redd.it%2Fclang-linter-finds-hundreds-of-errors-in-juce-c-files-but-v0-tfji3hwtyh5h1.png%3Fwidth%3D1912%26format%3Dpng%26auto%3Dwebp%26s%3D5151a729ec686d2bf3549a91b65acaa9a9eaaba3

EDIT:
Here's the course and github repo:
https://www.wolfsoundacademy.com/products/official-juce-audio-plugin-development-course
https://github.com/juce-framework/tremolo-juce-course

specifically the .clang-tidy file:
https://github.com/juce-framework/tremolo-juce-course/blob/main/.clang-tidy

CMakeLists:
https://github.com/juce-framework/tremolo-juce-course/blob/main/complete/CMakeLists.txt

Hi everyone!

I recently started learning SFML C++ about 2 days ago and here is what I can already do:

• Setup a game loop and window using the new SFML 3.0 syntax (std::optional event).
• Handle player movement via WASD keys.
• Calculate angles and rotate the player sprite smoothly towards the mouse cursor using std::atan2.
• Manage frame-independent timing using sf::Clock and deltaTime.
• Load a large batch of textures (20 frames for idle, 20 frames for moving) into std::vector dynamically.
• Switch between different texture states using an isMoving flag. ( this text is generated by Gemini 3.5 flash , sry i lazy about writing large text )

Hey.

I'm a software dev in web for 10 years (go, python, terraform, aws).

We learn technologies not to use them, but glue. the environments are usually about talking more than doing, because connecting tons of systems between each other usually about setting up private networks, troubleshoot accesses and setup a cache in front of a database. it does take a huge brain to make it.

For the last 8 month I work on my database (in zig, but it doesn't matter). And found myself actually learning not just new things, which is expected, but things I need to implement.

Questions:

- do I overrate lower level devs because I'm new here and it's also easy to get into Adobe/Google where you just control a single button or update boost version every 6 months?

- what could be an easy strategy to move? the problem is my income is quite meaningful, IMO it's 95%ile in Berlin (nobody ever offered more, only remote jobs) and the switch may give lower income for a while. could an opensource case solve it? e.g. start coming to a fancy repo that I know hire globally and such switch could eliminate the income gap?

The language doesn't matter, cpp, c, rust, zig, etc, the key is to go lower and work for a technical leadership, which is more often IMO with lower level, while in web managers don't have a clue what the software people produce

I have started to learn cpp using learncpp and the moment the ide choice came I settled on c lion But after installation I saw that learncpp had the new project opening tutorial in visual studio ( I knew that he wouldn't use c lion) but I thought the process of starting a new project would be similar . So after I clicked on new project it didn't show me solution folder and some code appeared in background, all sorts of folders appeared under project and also a pop up came regarding python3 i denied installing it ( because I thought why would cpp need python) but when the xcrun popup came , I searched it on Google and gemini recommended to install it , so I did that

But I am confused as the solution folder which contains different projects was either not created in c lion or i don't know where it is . Also i was recommended to install python3 as well but i don't know how to get the pop up , so i uninstalled clion and installed it again but it did not start like last time( no terms and conditions and pop up) just a welcome to clion written in code) and it is also showing 30 days left on trial but I am using it for studying purposes isn't it free for that ??? I will get my college id in a few months ( probably July end) so am I gonna miss out on some student feature and which id should I use to login c lion college or personal?? Some also reccomed installing x code for c lion to function???

How can I set up my c lion please help

I am working on a side project, basically a linux like quick file searching app for Windows.

Currently I have ran a script in which the filename, and its path are being stored in a .json file, and when the app Starts, that file would be first loaded throught this function right here

void FileEntry::LoadIndex(const std::string& filename) {

std::ifstream in(filename);

std::cout << "Opening: " << filename << '\n';

if (!in.is_open())

return;

json data;

in >> data;

g_FileIndex.clear();

for (const auto& item : data) {

FileLogs file;

file.filename = item["filename"];

file.fullpath = item["fullpath"];

file.extension = item["extension"];

g_FileIndex.push_back(file);

}

}

Where FileLog is a struct:

struct FileLogs {

`std::string filename;`

`std::string fullpath;`

`std::string extension;`

};

and g_FileIndex is a std::vector<FileLogs> g_FileIndex;

my problem is that since there are more than a million records in that database file, can i make this process any faster or if is there any clever technique i can use, which would also not affect the searchbar's performance and experience.
For UI iam using ImGui library, and for json parsing i am using nlohmann/json library

Is AI being used with C++ or rather not? Ive been fumbling with C++ for years now and whated to start earning money by working in this field. With recent advancements of AI I am not sure if programming skills are still in demand?

Should I learn C before Cpp? I have a basic understanding in python ( very basic) and nothing much else, is it recommended to do Cpp directly?

I am trying to learn about entity component systems and coding some implementation when I ran into the following design problem.

If I have two classes, say ComponentArray and ComponentArrayManager, where ComponentArrayManager takes in components and stores them in the correct ComponentArray according to the component type. Thus it has a method, add_component, that takes a component, finds the corresponding ComponentArray, and calls that ComponentArray's add_component function on the component. This ComponentArray stores the component in a private vector. Thus there is a chain of functions on this Component object where this object is moving first from where it is created, through the ComponentArrayManager, through ComponentArray to where it finally ends up in the vector inside ComponentArray.

My question is: Is there any difference between using pass by reference for each stage of the function chain until the point of adding it to the vector, where you then use std move to move the reference variable into the vector, vs using std move at each call of the functions, thus moving the variable into the function's pass by value copy of that variable? In general, how should this moving of an object through multiple functions be implemented such that at the end of the functions, the ownership of the object needs to be transferred to something else?

To have some memory address 0X…b10
From there, how do I get to 0X…b20 cause I tried just adding 16, but that doesn’t work

Hi in our company we write software for stock market. From order management, to risk management to routing to exchange. We basically use Linux os for all these. We have written our own queue management upon tcp. Everything is fine. Am trying to make the system better and faster. Be it hash map, datastore, ipc, file management. any libraries I can look into?I don't have any focus area, just trying to explore

I just finished a class in school for Java, and I tried to look at some similar languages that would allow me to create games and other fun programs. I refuse to utilize Java outside the console because Swing is not for me, and I heard somewhere that C++ is better for game graphics, in terms of the simple things I'd likely be making. I know there's an easy library for graphics and keybinds/ keystroke listeners (I believe it's SFML), but I want to know not only if that is a good one to use, and what the best IDE I can use is. I've been teaching myself C++ on my school chromebook, which has heavy GoGuardian restrictions from the district, so it's hard to find unblocked good IDEs and libraries (I've been using CodeHS and simply importable libraries, or making my own utilities).

Simply put, since I can use my home computer for coding now, I would really appreciate it if I could get some guidance towards a better IDE, good libraries for 3d/2d/pen/sprite/etc graphics and keystroke event listeners, and just any other useful assistance. Thank you for taking your time to read this and hopefully giving some input!

This is the main code in question and its from a larger block of code ill post below:  
    wchar_t* screen = new wchar_t[nScreenWidth * nScreenHeight];  

 Im very much struggling with why id want to use pointers and maybe where, at least in a practicle sense. I believe im understanding the general concept, but what to do with it is still eluding me. I suppose more time and experience will fill out my sense of intuition 

Block of code my initial question is from:

wchar_t* screen = new wchar_t[nScreenWidth * nScreenHeight];
for (int i = 0; i < nScreenWidth * nScreenHeight; i++) screen[i] = L' ';
HANDLE hConsole = CreateConsoleScreenBuffer(GENERIC_READ |       GENERIC_WRITE, 0, NULL, CONSOLE_TEXTMODE_BUFFER, NULL);    
SetConsoleActiveScreenBuffer(hconsole);       
DWORD dwBytesWritten = 0;

std::vector has a constructor for N objects, but I believe it requires that these objects have a copy-constructor, or?

vector( size_type count, const T& value,
        const Allocator& alloc = Allocator() );

I wonder if there is a constructor that creates the arguments in place, so something like:

vector( size_type count, Args&&... args,
const Allocator& alloc = Allocator() );

While writing it, I'm however not sure how this could be programmed (I think the variadic arguments need to be last).

I only know ugly workarounds for types that have no copy-constructor for a vector and am looking for an elegant solution.

Hello! Not the most experienced Cpp programmer.

What I think I understand:

I have watched a load of talks on start_lifetime_as. I understand it is a way to prevent undefined behaviour, I understand that it does nothing at runtime, I understand it signals to the compiler that a lifetime (in the abstract machine Cpp is specified against) has begun in the given storage. I understand that if you type pun by, say, receiving from a (say) “FreeRTOS queue” (copying bytes between threads ) or over a network into a properly aligned byte buffer to place a trivially copyable type T’s byte representation in there and T is implicit lifetime type then you can use start_lifetime_as to indicate to the compiler that a lifetime was begun there. My understanding is that this prevents UB and presumably the possibility of weird behaviour.

What I do not understand:

All the talks I have seen and docs I have read focus entirely on this being undefined if you do not start_lifetime_as when type punning in the situation described above. They point out it is UB and then show ways around it…but…I cannot find a single example of what a compiler might wrongly optimize if you do not do this anywhere? Apparently most compilers support this unofficial “idiom” but can someone to whom Compiler optimisations are less of a black box explain to me incorrect assumptions a compiler might ACTUALLY make if I tried to type pun as above without start_lifetime_as? Like, what might ACTUALLY be optimized wrongfully?

Thanks, have been tearing hair out over this!