QXmpp is pretty intuitive and easy to use. It uses Qt extensively.
Qt is the only third party library it is dependent on. Users need
to a have working knowledge of C++ and Qt basics (Signals and Slots
and Qt data types). The underlying TCP socket and the XMPP RFCs
(RFC3920 and RFC3921) have been encapsulated into classes and
functions. Therefore the user would not be bothered with these
details. But it is always recommended to the advanced users to read
and enjoy the low level details.