Lots of misinformation here.
IOS development which is what is popular right now which is written in Oracle C.
iOS development is
primarily done in Objective-C (I don't know what Oracle-C is supposed to be), but other languages are supported for non-UI purposes (app logic, etc) such as C and C++, and there are even projects out there for using .NET via MonoTouch.
Most Main stream applications are Written in C form mostly.
What is a "main stream application"? Save for a handful of legacy programs, most commercial applications are not written in C anymore; there are far better languages for writing end-user applications. Honestly, nowadays, writing an app (be it desktop, mobile, whatever) in anything other than a managed language isn't sensible unless you have direct need for lower-level hardware access and there are no libraries that allow for it. Even then, separating that logic out and wrapping it in a managed language usually makes more sense.
But best advice is go to the bookshop and get some books if your learning on your own. Nothing better then textbooks for learning.
Perhaps for some, but for many people it can be faster and [much] cheaper to simply download a set of tools and begin playing around with a language, using online documentation and help as a guide. Books on programming these days are often outdated by the time they hit the shelves, so be sure to keep this in mind when dishing out something like $50+ for them.
My advice to you (Sketcher) is to download a free development environment and start with a sample application in whatever language you choose. Hack at it, change things, experiment, until you begin to get the hang of things. Then start writing small applications.
Also,
Project Euler is a great set of programming tasks to go through when you want to learn the mechanics of a language. I highly recommend it.
The Beer Monocle. Classy.