在Ubuntu 24.04|22.04|20.04|18.04 安裝切換GCC編譯器

安裝
sudo apt update
sudo apt upgrade
​sudo apt install g++-12 gcc-12
sudo apt install g++-11 gcc-11

驗證安裝​
gcc-12 --version

成功訊息​
gcc-12 (Ubuntu 12.3.0-1ubuntu1~22.04) 12.3.0
Copyright (C) 2022 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

設定優先順序
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-12 100 --slave /usr/bin/g++ g++ /usr/bin/g++-12 --slave /usr/bin/gcov gcov /usr/bin/gcov-12

sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-11 80 --slave /usr/bin/g++ g++ /usr/bin/g++-11 --slave /usr/bin/gcov gcov /usr/bin/gcov-11


​檢查預設
gcc --version

已經更改為12​
gcc (Ubuntu 12.3.0-1ubuntu1~22.04) 12.3.0
Copyright (C) 2022 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

想進行變更
sudo update-alternatives --config gcc​