There is a learning curve, but at least with MELPA setting up Emacs is pretty easy. Company is a good autocomplete backend, Irony is a good back end for C/C++, and Company-Go and Emacs-Racer will do you for Go and Rust. Each of these can be installed by using interactive commands (M-x package-install), and configured with a few lines in your init.el (almost entirely just copying and pasting from the Github front page of the respective package).