Some time ago, I managed to find PPA featuring g++-4.7 build. However, I had to reinstall everything on my machine and I lost name of that PPA. Could anyone point me to it? I tried to find it again, but without any luck. I'm on Ubuntu 11.10 installation.
The Toolchain test builds PPA contains many packages including gcc-4.7.
You can add the repository using
sudo add-apt-repository ppa:ubuntu-toolchain-r/test
Then, to install it use
sudo apt-get update sudo apt-get install g++-4.7
To change the default compiler use update-alternatives
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.6 60 --slave /usr/bin/g++ g++ /usr/bin/g++-4.6 sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.7 40 --slave /usr/bin/g++ g++ /usr/bin/g++-4.7 sudo update-alternatives --config gcc
I haven't found a PPA for g++-4.7 but there is a gcc-snapshot package.
I guess you have to compile it yourself: http://www.lukaszbyczynski.com/archives/208
for my description of backporting gcc 4.7 to Debian stable.