Pointer Pain | Together C & C++ | Page 1

echo raven Jan 18, 2024, 4:27 PM

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So I need to add two non empty linked lists. A created an add function which adds the two digits from my linked list and store the answer digit in a new linked list. So to accomplish this, I need to pass a double pointer as an argument in my function and I am passing either the "head" pointer or "tail" pointer of my answer linked list. However I am facing an error at line 27.

sick wagonBOT Jan 18, 2024, 4:27 PM

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glacial pond Jan 18, 2024, 4:42 PM

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*ans is a LinkedList*, since ans is a `LinkedList**~

echo raven Jan 18, 2024, 4:51 PM

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Yeah so the -> operator should work right?

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But it isn't.

proper tide Jan 18, 2024, 4:53 PM

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(*ans)-> next

glacial pond Jan 18, 2024, 4:53 PM

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(*ans)-> should work

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frick sniped

echo raven Jan 18, 2024, 4:55 PM

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Nah it ain't working.

glacial pond Jan 18, 2024, 4:55 PM

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It's working as in it's compiling. It just means your code is valid, but incorrect.

proper tide Jan 18, 2024, 4:56 PM

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Maybe dereferencing a null pointer somewhere

echo raven Jan 18, 2024, 4:56 PM

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I guess that might be the issue.

glacial pond Jan 18, 2024, 4:57 PM

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No. You're using a pointer that you already deleted

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Compile with debug symbols and it should show you where you're trying to access it at

echo raven Jan 18, 2024, 5:00 PM

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Can you guys help me debug it?

glacial pond Jan 18, 2024, 5:00 PM

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looks like homework

proper tide Jan 18, 2024, 5:00 PM

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Nah it’s just lc

echo raven Jan 18, 2024, 5:01 PM

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Yeah its leet code.

glacial pond Jan 18, 2024, 5:03 PM

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yeah, I don't touch LC very intentionally. good luck

proper tide Jan 18, 2024, 5:05 PM

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Debugging in LC sucks. You should probably run it on your own machine with GDB or some other debugger

echo raven Jan 18, 2024, 5:07 PM

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Hmm... I made sure that I am not dereferencing a null pointer.

echo raven Jan 18, 2024, 5:07 PM

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proper tide Debugging in LC sucks. You should probably run it on your own machine with GDB o...

Problem is...... Idk how to use a debugger.

glacial pond Jan 18, 2024, 5:09 PM

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Google

echo raven Jan 18, 2024, 5:23 PM

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Wait, so it apparently says I am using a heap memory after freeing it? But I ain't freeing anything.

oblique swallow Jan 18, 2024, 5:31 PM

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echo raven Wait, so it apparently says I am using a heap memory after freeing it? But I ain...

the os do it for you

echo raven Jan 18, 2024, 5:31 PM

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But only after executing the program right?

oblique swallow Jan 18, 2024, 5:31 PM

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no

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when it ends a task

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use smart pointers

echo raven Jan 18, 2024, 5:41 PM

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Well I was thinking of doing some optimisation but looks like I have to do it the old fashioned way.

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Thanks for your help everyone.

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!solved

#Pointer Pain