I worked many years ago with the "editor, compiler and linker" and working many years and now using Visual Studio:)
Actually, the only necessary element besides these is a debugger (a system which can temporarily break execution of the program and show where we are and the values of variables). Integrated help system also a good option but could be replaced by Google.
If you have all these elements, you can work. There are very good editors now. But having everything within one program (IDE), as in Visual Studio, is much more _convenient_. You don't waste time jumping here and there. It is necessary also for IDE to be a good one. I think Visual Studio is.