I have set up an c/c++ IDE according to this video (https://www.youtube.com/watch?v=Ib914gNr0ys). Everything works ok except that the auto completion of cedet didn't work.
After googling a lot, this answer (https://stackoverflow.com/a/18860526/3824053) helped my.
So, I don't know where I am wrong? Auto completion in that video actually works properly, but the same configuration does't doesn't work for me.
I use emacs version 24.5 running on Mac OSX 10.10.4.
I tried a lot but still failed. I now use company instead of auto-completion, it works fine and stably.