ask for explain !

please i wanna know what know what "vw_set_ptt_inverted(true);" mean ?

It looks like a function call.

where did that code come from (post the code and links)

please i wanna know what know what "vw_set_ptt_inverted(true);" mean ?

It is a command from the virtual wire library relating to the set up of a "push to talk" (PTT)pin that may connected to the transmitter controller. Default is that he PTT pin will be set so that HIGH enables the transmitter unless Inverted (true) if you desire the ptt pin to be inverted so that LOW will enable the transmitter.