You cannot program directly on the ipad (unless, possibly, you jailbreak - someone correct me).
To program the ipad you need the xcode program from Apple (free) and a Mac to run it on (not so free). The preferred language for xcode is objective-c, which is a version of c based on smalltalk, I think. You can use c if you want, but the whole exercise becomes much harder.
At first you can run your programs on the provided simulator within xcode, but to get them onto an iPad you must pay Apple $99 for a developers licence. ( or jailbreak your device )
There are many different books available on Amazon.com and other places about ios programming, but most of them are only in english. I know a few have been translated into italian, but I don't know about other languages. I imagine that the major european languages along with japanese and chinese would be found as translations of some of the books.
Do not be discouraged by all this - it is very satisfying to get your first program running! Good luck!
Sent from my iPad 2 using iPF