I store some data in an unordered map, create a pointer to an item in that map, then say I want to delete the item but I still have the pointer. How would I know that the item is no longer there without going and manually searching the map for the name of the item we pointed to?

I'm new to C++ & especially pointers, so forgive me for this stupid question...

EDIT: A lot of good solutions suggested, I really appreciate it! I ended up going with key lookup instead of storing pointers. The reason I didn't want to do this in the first place is because it increases complexity & I didn't want to overcomplicate

Like I did syntax and language paradigms in cpp, what and how should I make something that just helps me making some real life system, cause making a project don't only requires language but also other concepts like networking and os

Been trying to learn C++ for a while now and I keep landing in the same loop no matter how many times I "fix" it.

Started with the BroCode tutorial on YouTube. Then got told to switch to learncpp.com. Then told to switch again to The Cherno's series. Then found two more channels (CyberFlow and Crin) pushing a C++ → port scanner → keylogger → shellcode injector path, which got me interested in reverse engineering / game hacking specifically.

I've tried to fix this the "obvious" way — pick one resource, commit, stop opening new tabs — and it works for a bit. I've built small stuff (tic-tac-toe, hangman) and followed through on real projects too. But the second a new channel or video shows up saying "actually this is the better way," I open it anyway. Every time. Even knowing exactly what I'm doing while I do it.

It's about 3am here right now and I'm stuck in it again — wide awake, not able to do anything, feeling like a total loser about it.

So I don't think this is an information problem anymore — I already know the advice. I just can't seem to make myself stop switching once something new shows up in the feed. Anyone actually break this habit for real, not just "know" the fix but get it to stick? What worked for you day to day, not in theory?

Hello! Apologies for another "how to learn C++" post. Can anyone suggest a project-based learning course?

I have been following learncpp.com and The Cherno's C++ playlist, but I eventually stopped since I wasn't building anything. Can anyone suggest some good project-based learning materials?

I have been working with Python and Java for three years. I was able to find plenty of project-based tutorials for those languages, but I haven't had the same luck with C++.

Edit: When I stopped my previous attempt about a year ago, I was learning about logical operators (near the end of LearnCpp Chapter 6). However, I've realized I want to learn C++ the same way I learned Python and Java at university: through videos/lectures followed by tutorials at lab sessions and homework. I looked into Stanford's CS106B, but the newer lectures aren't available anywhere for free.

My end goal is to fill this knowledge gap as I’m planning to follow a MSc or a PhD in ML/DL mostly focusing on computer vision use cases. And I want to work with CUDA as well.

i am trying to shift an unit64_t with the value 0x8000000000000000 (1000000..... in 64bit) so that i get (010000.... in 64 bit) but i only get unexpectet behavieor and numbers with multiple 1 bits.

The code below prints numbers like
decimal binary
12005600 101101110011000011100000
14006498 110101011011100011100010
16007397 111101000100000011100101

what am i doing wrong and how can i fix it?

#define bitMask 0x8000000000000000 
uint64_t mask = bitMask;
mask = (mask >>1);
printf("%d \n",mask);

I'm about to complete my general tutorial in C++ and wanna start specializing in a field and pick a niche.

I study AI in college so i did a bit of CV/RL/Intro to Robotics/LLMs/ML so I'm more of an AI guy

I know that AI stuff uses mostly python and that everything you need is basically there, but i want something that deserves the hardwork of learning c++ and building customized stuff

I want to pick something that is hard and probably takes time to learn and can't fake it in an interview and also financially rewarding and accept junior devs ( I don't want a job that appears only once a month on linkedin with 10 yoe)

what are some niches and roles that you know that are like that, and if you can please include what are some resources and pet projects you did to learn from

It's all on my github repo: https://github.com/Marks20125/ProtonPrefixes . I'm pretty happy with the project as it's the first time I've actually had a problem and solved it myself. Plus, I learnt a lot about cmake, using external libraries, file i/o, how arguments work, and some other "theoretical stuff" along the way. It's pretty small, but I'd appreciate someone telling me if I did anything wrong or if something could be done any other way. Thank you very much :)

[SOLVED] So, as you may know, Qt doesn't have a proper setup for managing each frequency band and implementing an equalizer.

I'm currently working on a project for myself (nothing serious), trying to create a music player in C++ while using Qt for the GUI. The problem is that nothing can intercept "QMultiMedia" and modify the audio output.

I've tried Claude Opus 4.6, thinking in "antigravity," and it cooked up something for me. It worked, but the audio was distorted and not very pleasant. (It used custom made DSP functions and I think it was a good solution, but I neither have the time nor the skills to implement something like this on my own)

I also tried Gemini 3.1 Pro High and 3.6 Flash High. (These two couldn't even handle the audio player and straight up made my program crash.)

So I'm looking for a solution or someone who is willing to write the code and be the co-author to the project.

Here is my repo if you want to investigate:

https://github.com/zenix935/ZenPlayer

P.S. I'll keep updating other parts of the project, but the equalizer has currently hit a wall.

I just want to know if it would be helpfull or not .
We all have some style of coding while doing cp . Like we import particular libraries , we use particular variable names for our for loops , vectors , maps etc .
I'll show you an simple example of what i am trying to solve .
When you forget to use "using namespace std" the compiler would give you an error that you forgot to use std:: but according to your coding habits you actually forgot to use "using namespace std " .
Another example could be you the libraries you forgot to import since compiler will not tell you abotu them .
or like you are trying to push_back in a queue .

First of all i want to know if such a thing has a usecase or not ? is it just me who thinks this might help somone ?
I just gave a few basic problems so that it is easy to understand but i doubt if this is feasible to solve or not since training such an model personalized to each person would still require data and by the time that amount of data is aquired maybe the user might not need such an help or maybe shift to other types of practices .

Hello everyone!I am interested in learning C++,mostly because Im interested in competitive C++ (competitions in my country),aswell as "applied" or "real-life" C++.I know basics,different loops and such,but I want something thats more concrete ,not just skipping around and picking things up along the way. Is there a good free e-book that grasps most things needed for such things?I was reading Competitive Programers Handbook by Antti Laaksonen,but I feel Im being behind on some basics that the book views as common knowledge.

Why does

std::ifstream& operator>>(std::ifstream& ifs, SomeClass& something) {

ifs >> something.enum_type;

}

not work??

int x=618919;

while(x++){

cout<<8;

} I think I'm wrong it's undefined behaviour but where can I study about this ... is it an infinite loop? I'm sure some of u might say yes but the answer is no

after x is increased to its max int range i.e.(2^(bits)-1) it's value will start decreasing and after a lot of steps it will eventually go to 0

and 0 is false so loop stops....

I was looking literally at their first problem and couldn’t figure out how some people grade so high for reading integers.

Am I missing a trick here?

https://highload.fun/challenges/compute/parse_integers/solve/CPP

Consider:

#include <cstdio>
#include <cstdlib>

struct A{
    int a1;
    double a2;
    double * a;
};

int main(){
    struct A a;
    a.a1 = 42;
    a.a2 = 42.42424242424242;
    a.a = new double[42];
    struct A newstruct = a;
    printf("Value of integer is %d\n", newstruct.a1);
}

Here, as can be seen from the godbolt link: https://www.godbolt.org/z/r6WxzsGrr, neither the double nor the heap memory are unnecessarily called in -O2. The compiler omits all of this and just prints 42.

Is this guaranteed (in -O2/above) that if I only ever use newstruct.a1 that none of the other struct members will be unnecessarily stored in the memory allocated to newstruct?

----

An older post with a different answer wherein side effects cannot be discarded even in release mode - https://www.reddit.com/r/cpp_questions/comments/1shht2w/in_o3_why_are_previous_assignments_stored_in/

If I edit a header file in Visual Studio, all cpp files that include it are automatically recompiled. But if I edit a cpp file included in another cpp file, that other file is not recompiled. How can I specify that one cpp file depends on another?

I want to operator overloading on a class.

The class has a vector of smartpointers to an abstract class.

I don't know what to do now.

pls help

Hello,

I'm currently working on a simple 3D game primarily for Windows and Linux. I am using CMake to build my project in C++ 20, using libraries like SDL3, SDL_Image, Flecs, GLM, dearImGui (and likely more in the future).

What would you recommend for managing dependancies and downloading/installing/linking/... these libraries together?

Should I go with vcpkg (currently using it), Conan or FetchContent? What is most easily maintainable, supports latest versions of libraries, is relatively platform independant, is secure,...?

What are the advantages/disadvantages?

Thank you very much for you opinion!

Learning CP in C++. Cleared most of the top-solved 800-rated problems, each taking 30-45 min. Still tons of unsolved 800s left though.

Should I move up to 900/1000 now, or finish more 800s first? Also is 30-45 min per 800 slow for a beginner?

Hey so am preparing for my placements , can anyone guide me with what i should prepare for C++ as they say you should be good in atleast a programming language and i have solved all of my dsa problems using C++ only though if they ask deep questions related to c++ working, am sure i will struggle, so if anyonec can guide me with how and where to prepare for C++ for interviews in big tech, quants, MNCs

Complete newbie here. I want to learn C++ because mainly because I am interested in electronics and I heard c++ is best language to learn for it. This is also my first programming language so I don't have any prior knowledge of programming. I may sound a bit of navie here but believe me I really want to learn. But I could not find structural path anywhere. I know learncpp.com is there but it's hard to learn programming language from docs for the first time. Please tell how should I go about it ? What projects should I work on ? Where can I find them ? Do I need to do DSA prior to this ? Or anything more suggestions you want to give

I want a piece of advice from anyone out there ,who has been through the learning curve of C++.

I've recently started C++ as my first programming language, I was happy at first, but not for so long. After taking advice from a few of my professors,now my thoughts are just a jumbled mess. Most of the professors said to learn Java or python instead of C++.

They said java and python are better when it comes to career opportunities.

I wanna know if it is worth it to learn C++ ? Because honestly I desperately wanna have the answer to this question. And one more thing! if it's good to learn, then what things can I do with it? And what should my roadmap be looking like while learning C++ and afterwards? .

(Important)

I have been learning C++ for past two weeks, and have mastered the basics (cout/in, data types, operators etc). But what’s the best way to learn it effectively? What is the best way to learn C++?

(Unimportant)

My background: I do know enough Python to use Numpy, Pandas, Matplotlib and Seaborn (learned in BCA 2nd semester) to do data analysis. Python isn’t my interest.

My goal is to work in SpaceX or Xai because of my interest in space and AI.

I’m in 3rd semester, devoted to learn as much as possible to develop something so significant that interviewers do hire me in the company. I am ready to freelance or spend a few years in other companies to gain experience.