Basic question related to QT...

Centos 6.4 comes with QT4.
When I open it (Application/Programming/QT4 Designer) and drag a push buttom, it dosen't generate code. I have to go to the form/view code to generate the code. But it seems the code is not interactive with the gui. When I watch some videos related to QT, it seems the interface is different. I used yum install qt and it updated some files but still I don't have an interactive menu and code.

When I am using qt --version it shows (Qt 3.3.8b) which is not the corrdct version it supposed to show. help/about qt shows 4.6.2.

Is QT coming with centos has the same feature as if someone install QT?

CentOS is usually (but not exclusively) meant for use in servers. Meaning it's stable software version with minor enhancements and bug fixes backported and thoroughly QA'ed. It's a limited set of software compared to that you would find in for example the Fedora repos. Those software versions are more recent and there's more (development) packages to choose from.