how can I use cxx-pretty-print to print out the syntax tree of g++?

[yuyang08]

Dear g++ developers and users,

I am interested in the syntax tree that g++ parser constructs. I notice
there
is a file  cxx-pretty-print.c  in  the source directory. How can I use
it to
pretty print the syntax tree , or other abstract representation out?

Thanks a lot!

-Andy