What is the best Approach to deleting data here?

[weak wren]

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[snow ermine]

I'm not entirely sure, however...

generally with something like this the approach would probably be to return an iterator

then you can check if iter == q.end(); to see if it's valid

or, alternatively, maybe throw an exception if you try to pop something from an empty queue, because that would be not dissimilar from accessing an out of bounds array index

[weak ravine]

well, what do you need to delete why? what is the function going to return if the thing was deleted?

[thorny grail]

I’m just trying to understand memory management and leaks. I believe if I don’t delete it my program will have a leak?

[weak ravine]

well, if the thing was created via new, you generally will need to delete it yes

[thorny grail]

Oh, but in this case it’s both

Not*

So I won’t have any leakage

Leaks*

Is that correct?

[weak ravine]

it's pretty simple: do you delete everything that you new?

[thorny grail]

Well I just started cpp, so naturally I want to say yes.

In Java garbage collector does it automatically

[weak ravine]

well, C++ is based on the idea of simply not producing any garbage in the first place

then there's also no need to have someone come pick it up 😉

[weak ravine]

well, where do you new these things and where do you delete them?

[thorny grail]

Like in general? i would new when i want to create a new instance of an object? such as Node* temp = new Node(params); then delete after it has been used/outputed to watever needs it?

[weak ravine]

i mean in your code

if you use new, you need to delete

simple as that

[thorny grail]

thats the only case? for example in my Node* temp = qFront; i dont need to delete the temp?

[weak ravine]

temp is not created via new

so no

[thorny grail]

man, this sounds dumb but this is what my professor said.

[weak ravine]

yeah that makes sense

qFront is what?

[thorny grail]

a node?

[weak ravine]

a pointer to a node it would seem

i'm assuming that node it points to was created via new

so what's temp then?

[thorny grail]

temp is just a copy of qFront that stores the data to be deleted so that i can re arrange the pointers

[weak ravine]

right

so temp also points to the node that was created via new

[thorny grail]

yes

[weak ravine]

and then you delete temp

[thorny grail]

yes

[weak ravine]

so you delete the node that you created via new

[thorny grail]

Correct.

[weak ravine]

well

then if we assume you always take everything out of the queue, there should be nothing left that wasn't deleted

ofc you still have the problem that your dequeue function doesn't return anything

[thorny grail]

right.

[weak ravine]

well, what should it return?

[thorny grail]

Well, if im following you correctly. since there wont be anything in the queue it should return null since there wont be anything there?

[weak ravine]

i'm not following i'm afraid

based on the screenshot, i would have assumed that it should return a CustomerData

[thorny grail]

yes! it returns an object of that type

correcto

[weak ravine]

what's that type?

[thorny grail]

CustomerData?

[weak ravine]

yes

[thorny grail]

so. maybe i need to extract that data from the node instead?

the node holds CustomerData data

[weak ravine]

yeah that sounds like a good idea

random note: one really shouldn't use NULL in C++

use nullptr instead

[thorny grail]

what would you have me use then? just dont assign?

oh

[weak ravine]

NULL is a C thing. it exists in C++ solely for the purpose of backwards compatibility with C.

there are various issues with NULL in C++

it's bad practise to use NULL in C++

[thorny grail]

good to know. i can fix that no prob

[snow ermine]

use nullptr instead

[snow ermine]

.

[thorny grail]

what do these symbols mean next to the variables?

just random side question

[weak ravine]

they indicate what kind of thing it is

variable, class, etc.

[thorny grail]

i see so the fact that nullptr and Null have different symbols doesnt mean one is c and the other is c++? lol as like a shortcut to know which is right

[weak ravine]

no

it means one is a kind of value and the other one is a type

or smth like that

tbh, not sure what the symbols there stand for exactly. would have to consult the documentation of your ide for that

[snow ermine]

nullptr isn't a thing in C

so that gives you part of your answer

[weak ravine]

(yet)

[snow ermine]

indeed, I wouldn't doubt it may be forthcoming in newer C language standards, but I don't pay any real attention to C, nor C language standards, either historical or forthcoming

[weak ravine]

iirc, C23 will introduce nullptr

[snow ermine]

TIL

[weak ravine]

not that it matters because who writes C anyways amirite 😛

[snow ermine]

insert <CHEEKY_QUIP_ABOUT_C_BEING_ABSOLUTE_GARBAGE>

I mean, it arguably gave us C++, so it's not 100% bad, only like 99.9999% bad

[thorny grail]

do you think im getting this now for not using New or is this a issue with something else

[weak ravine]

no, you're getting this because you don't have a main function in your program

[thorny grail]

crap sorry that was the wrong ss

[weak ravine]

well, you're getting those because those functions haven't been defined

[thorny grail]

omg i just realized its a different function as well from what i was working on originally.

https://tenor.com/view/lord-pleas-help-oh-no-gif-25461814

[weak ravine]

no worries

linker errors specifically are something most people struggle with at the beginning

[thorny grail]

dawg i dont understand its properly defined at the top. how could something be undefined if i can see it in the file properly written out and declared.

[snow ermine]

I mean, how good is your imagination

short answer: lots of ways

[thorny grail]

i didnt even write the implementation though. i was given the files to edit LOL

[snow ermine]

🤷

Show Code ™️

[thorny grail]

what part of the code?

the tester has over 600 lines

[snow ermine]

this part of the code https://stackoverflow.com/help/minimal-reproducible-example

in other words: the relevant parts, but all the relevant parts, but only the relevant parts

indeed most of us probably don't want to sit and read 600 lines of test harness if that doesn't relate to the actual core functionality

[weak ravine]

which file where? are you compiling that file?

[thorny grail]

i mean if im getting a undefined reference im assuming its just my headers?

[weak ravine]

no

undefined reference means the function is used in your program but not defined anywhere

[thorny grail]

Yes, i am compiling my file

[snow ermine]

time to learn what a TU is

and probably, related, what it means to create and use your own libraries, both shared and static

[weak ravine]

does your project consist of only a single file?

[thorny grail]

No, so i have a Queue.h and a Queue.cpp with the implementations additionally im using Queue.h in a tester just to test the functions.

[weak ravine]

and how are you compiling your program?

[snow ermine]

if you have, for example, main.cpp, foo.cpp, and bar.cpp then you need to compile all of them

[weak ravine]

^

[snow ermine]

in your context, presumably you want to compile all of them into a single result

[thorny grail]

yea i know. one second im trying to re do it

dont know maybe the VM was running really slow or something but its working now...

this is how i was compiling i just reset VSC and it ran lol

Thanks for ur help dot 🙂 im sure ill have more questions in a bit but thanks for now

!solved

[weak wren]

Thank you and let us know if you have any more questions!

[SOLVED] What is the best Approach to deleting data here?

[weak wren]

@thorny grail

This question thread is being automatically marked as solved.

[thorny grail]

BRUH OKAY! I already closed it

!solved