install qt5 ubuntu code example

Example 1: install Qt5 ubuntu 20.04

sudo apt-get install build-essential
sudo apt-get install qtcreator
sudo apt-get install qt5-default

Example 2: install qt4-qmake ubuntu

sudo add-apt-repository ppa:rock-core/qt4
sudo apt update
sudo apt install qt4-default
sudo apt install qt4-qmake
#to remove it
sudo add-apt-repository --remove ppa:rock-core/qt4