I dunno, did you specify the correct board and platform (as
esp32doit-devkit-v1 certainly ain’t it!)? As if you didn’t, it ain’t gonna work!
That’s a whole different issue, partly related to embedded processors and mostly related to Arduino. You only have to google ‘Arduino iostream’ and you’ll get the same answer I’ll give now… you’re programming a microcontroller, not a desktop computer… iostream ain’t valid with Arduino!
Fair enough. If/when you want to pick this up again, please take care to start from the basics, and work your way through. Get the basic (ie. empty) project up and compiling, and uploading to the board. Ensure that any code or libraries you use are meant for that framework (i.e. Arduino, ESP-IDF) , else it is only going to end in tears and/or frustration when you hit issues because you are trying to use library X (meant for use with framework Y) on framework Z, and it doesn’t work.