[PD] programming resources C\C++ to learn how to write externals for pd

[adrian.g]

 Hi. I am looking for some resources for learning C\C++ programming in a context of DSP (I'd like to be able to write pd externals some time in the future). 

I have recently finished reading "The Scientist and Engineer's Guide to Digital Signal Processing" and I managed to go through half of the Addison Wesley's "C++ Primer 4th Edition" (and I'll probably keep reading it), but I feel that it would be good to learn more in a context of what I am really interested in. 

The exercises in the C++ Primer are very dry and the examples in The Scientist and Engineer's Guide are all in BASIC (I could probably try to rewrite them in C++ as an exercise). Could anybody show me the light and point me to some books, or online resources (tutorials, bits of code easy to comprehend by a beginner) that could help me achieving my goal? 

ps
I was just wondering if I should start from learning C and then go to C++ or just learn C++ and then learn bits of C along the way?

Thanks for reading this!! :)

Adrian Gierakowski