Ok, so teacher (which should be something like a professional dev or whatever) assigned us a homework for a Christmas (I dont care, I can complete his assignments in like 10 minutes max). We have to do some simple shit in C++, just some loops and input + output. Nothing hard. He challenged me to write it as short as possible, so I did. My classmates have codes around 60 to 70 lines long (after propper formating). I made it 20 lines long using some pointer magic and stuff like that. I tried my code, it ran fucking perfectly, so I sent that to him. He replied that the code does not work. I tried to recompile it and it ran perfectly. Again, it does not work. Afeter 13 fucking emails he fucking finally sent me the error message. Some fucntion was not found (missing some library but literally everywhere else it works without it...). Thats strange, because it run perfectly on my Fedora with CLion, so I switch to Windows and try to run same code in Visual Studio (which we are using in school btw). Works perfectly. So I start arguing with the teacher more and more. I tried around 10 online compilers. Works fuckng everywhere. Teacher is pissed, me too. So I rewrote my whole code, added comments and shit, reinvented wheel literally everywhere. Now I have C99 standardised code over 370 lines long that run even on a fucking arduino after changing input output methods so it can work with it. It (suprisingly runs) on his PC too.

After a bit more arguing, he said that he is using CodeBlocks from fucking 2015. Wow. Just fucking wow. Even our school has some old Visual Studio (2007 I guess) and it worked there.