The Pi is Linux machine so you could use C if you wanted.

You should only need to use Python if you want to use hardware with no C support.

On the other hand Python is quite popular so you might want to learn it anyway.

There is a lot of stuff on the web  - trawl about until you find something you like.

Bookwise, I started with Beginning Python, Magnus Lie Hetland - published in 2005 - I don't much recommend it (not because there is anything wrong with it but because it's 10 years old now.)

MK

Has Mike says you can use "C" on the RPI just fine the Compiler is supplied on the latest  Rasbian images with out needing to install it so you an just continue with this.

Yes most released software on the RPI is in Python generally because it's simpler than C if you still want to learn it I would suggest starting a project that requires it and this should push you to learn.

Alternatively how about taking a computing module on EdX that does Python like the MIT one... It's free even!

(or 50$ for an exam  if you want a certificate)

I suggest 'Learning Python' by Mark Lutz and David Ascher and published by O'Reilly as it often explains the Python way of dealing with c programming tasks. There are lots of examples and exercises (with solutions). Once you get to grips with the Python objects, the very best resource is the wonderful,

https://www.python.org/

In fact, browse the site, first, and see if the downloads and on-line references, tutorials and other documentation are enough to get you going. Once you get functions, strings,  tuples, lists, classes, dictionaries and the like, the documentation should make lots of sense.

Imports are to Python as includes are to c. Python imports are modules which add functionality, but most of the ones you want are included by default when Python is installed (by default in the Pi). The Pi also has the IDLE IDE installed for both the current Python 2.7 (widely used across many platforms) and Python 3 (the future). I have written Python programs on the Pi which access the command line, use COM ports and the Tkinter GUI module and they run with minor changes on Microsoft Windows by installing the same modules.

As Michael says, you can program in most languages using the Pi. However, Python on the Raspberry Pi comes as standard with a module to access the GPIO features (although the more complex issues such as I2C, serial and PWM have yet to be added). The Broadcom chip is complex and many of its features are entwined with the Linux operating system. It may not be that straight forward to use every GPIO feature. Also, the Pi2 puts its control and read registers at different addresses. The joy of using the Python modules is that the ins and outs of Linux and Broadcom are already sorted. There are plenty of examples of PWM and I2C programs written in Python just using the simple I/O pins rather than the dedicated Broadcom pins. However, C would be the way to go if you want precise time dependant programming as Python is interpreted and has the occasional mid-program tidy-up. Even pre-compiled Python may be a problem.

I just checked with the Synaptic Package Manager and GCC is already installed in the Pi. Java is in the repository as is Fortran, Ada, Objective C, C++, Cobol... you get the idea! There are lots of others such as Ruby and Forth. However, if you want to use c or c++ you will have to do a fair amount of research to drive the GPIO hardware to the full without killing the operating system. All the usual OS stuff is available to C and C++.

Introduction to Computer Science and Programming Using Python

edX - 6.00.1x is an introduction to computer science as a tool to solve real-world analytical problems

https://www.edx.org/course/introduction-computer-science-mitx-6-00-1x-0#.VPSLYI6VkUM

Scott

If you haven't found it yet, http://www.themagpi.com/ is a free magazine about all things RPi. There are many projects in python as well as other languages. All the issues are available for download. There are 30 issues now plus some specials.

Python is a high level language and it allows fast problem solving. If it turns out that the problem needs more speed, there are linkages to "C" so the low level stuff can go fast.

I took a free course taught by the Google self driving car guy from https://www.coursera.org/   The course was great, but I don't think a complete python novice would appreciate it (unless fairly fluent in some other languages). There are other courses that are a bit more basic.

The edX course recommended by Scott is great.

Also check out learnpythonthehardway.org

Just a random thought, but what about JSON? It can run in a web page environment but also outside!

Clem

Life long friend of mine has started some interesting stuff with Code Red and posted on YouTube https://www.youtube.com/watch?v=xoQ_Fs31xtM

Enjoy

Peter

With a project, preferably your own that you are interested in so you are likely to stick with it.

Failing that the EdX Computing course is very good as it teaches Python in a very structured manner and is free!