How to find Version of Qt?

Question

How do I know which version of Qt I am using? When I open Qt Creator it shows \"Welcome to Qt Creator 2.3\". In the build setting, however, it shows Qt Version 4.7.1.

Answer 1

For qt4 :

QT_SELECT=4 qmake -v

for qt5 :

QT_SELECT=5 qmake -v