I am on Debian 7.9 and this question may seems very familiar to you, I have also seen some links, but when this was answered the GCC-5 was in testing place they suggested it as a work around, since we now been along with 6.X, is there any direct command like the below to install the newer version of G++
sudo apt-get g++-5(this doesn't work and say the pack not found)
And also its is more helpful if any suggestion passed along to replace the old g++ with the new one(if I successful with the installation)