ubuntu install geckodriver

C++
sudo apt install firefox-geckodriverwget https://github.com/mozilla/geckodriver/releases/download/v0.24.0/geckodriver-v0.24.0-linux64.tar.gz
tar -xvzf geckodriver*
chmod +x geckodriver
export PATH=$PATH:/path-to-extracted-file/.
Source

Also in C++: