I have been wondering about this for a while.
What applications is programs like visual studio programmed in? But also, where is operating systems like android, ios and windows written in?
I just find it hard to imagine how developer environments are/were made, when they didn't exist! Get me right, I know that other developer environments probably existed at the time that they were made. But which? There is probably some logical explanation to this, and I would be happy to get to know it!