turtle_tf_demo.launch goes wrong when replaced with c++ compiled nodes

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I tried to run the TF tutorial and fist launch:

roslaunch turtle_tf turtle_tf_demo.launch

and it worked fine.

And then I noticed that the launch file would run nodes written in python. So I replaced them with the C++ ones and launched it again. However, turtle2 got frantic....

https://www.dropbox.com/s/mw2ds061oprzgx0/TF_problem

I've checked the C++ code of the broadcaster and listener in turtle_tf, as long as the Python ones. In terms of their functionality, there weren't any difference between the C++ and Python ones, but the demo results turned out to be a lot different.

How can I solve this problem? Thanks~