I install ubuntu 12.04 in my notebook and I use c++. I want to use c++11,so I want to upgrade my gcc to gcc4.7. I do like this: sudo add-apt-repository ppa:ubuntu-toolchain-r/test sudo apt-get update sudo apt-get install gcc-4.7 sudo apt-get install g++-4.7 but when I run "sudo apt-get install gcc-4.7", it just can find gcc-4.7-base not gcc-4.7, and when I run "sudo apt-get install g++-4.7", it can find nothing... Today, I want to install the "bumblebee" and do like this: sudo add-apt-repository ppa:bumblebee/stable sudo apt-get update sudo apt-get install bumblebee bumblebee-nvidia sudo reboot but when I run "sudo apt-get install bumblebee bumblebee-nvidia", it tells me the packages can't be find. The ways I methoded are specially use to ubuntu 12.04, the links is: Installing gcc 4.7 https://wiki.ubuntu.com/Bumblebee#Installation What can I do? Thank you!My email is [email protected]