Run the following in the terminal:
Install the gcc-7 packages:
sudo apt-get install -y software-properties-common
sudo add-apt-repository ppa:ubuntu-toolchain-r/test
sudo apt update
sudo apt install g++-7 -y
Set it up so the symbolic links gcc, g++ point to the newer version:
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-7 60 \
--slave /usr/bin/g++ g++ /usr/bin/g++-7
sudo update-alternatives --config gcc
gcc --version
g++ --version
# This one if you want the **all** toolchain programs (with the triplet names) to also point to gcc-7.
# For example, this is needed if building Debian packages.
# If you are already are root (e.g. inside a docker image), remove the "sudo" below.
ls -la /usr/bin/ | grep -oP "[\S]*(gcc|g\+\+)(-[a-z]+)*[\s]" | xargs sudo bash -c 'for link in ${@:1}; do ln -s -f "/usr/bin/${link}-${0}" "/usr/bin/${link}"; done' 7