linux 安装不同版本的C++

ubuntu20.04

apt-get update
apt-get install -y gcc-10  g++-10
update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-10 30
update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-10 30

根据需要切换不同的编译器(gcc/g++)

 update-alternatives --config gcc

There are 2 choices for the alternative gcc (providing /usr/bin/gcc).
  Selection    Path             Priority   Status
------------------------------------------------------------
  0            /usr/bin/gcc-10   20        auto mode
* 1            /usr/bin/gcc-10   30        manual mode
  2            /usr/bin/gcc-8    20        manual mode
Press  to keep the current choice[*], or type selection number

CentOS 8.4

yum install gcc-toolset-11 gcc-toolset-10 gcc-toolset-9
alternatives --install /usr/bin/gcc gcc /opt/rh/gcc-toolset-9/root/bin/gcc 20
alternatives --install /usr/bin/g++ g++ /opt/rh/gcc-toolset-9/root/bin/g++ 20

alternatives --install /usr/bin/gcc gcc /opt/rh/gcc-toolset-10/root/bin/gcc 20
alternatives --install /usr/bin/g++ g++ /opt/rh/gcc-toolset-10/root/bin/g++ 20

rm -f /usr/bin/gcc /etc/alternatives/gcc
ln -s /opt/rh/gcc-toolset-9/root/bin/gcc /etc/alternatives/gcc
alternatives --config gcc
alternatives --config g++

 7.5以前的版本通过 scl enable devtoolset-7  bash来切换：