undefined reference

[toxic trout]

When your question is answered use !solved to mark the question as resolved.

Remember to ask specific questions, provide necessary details, and reduce your question to its simplest form. For tips on how to ask a good question run !howto ask.

[arctic horizon]

this is the code

damn it's too long

but the gist of it is that

why there's undefined reference error even though i programmed the function correctly

or idk if i have a mistake or not. im just still learning C so pls help me