redache

This isn't true at all. I've contributed to Open Source projects in languages I've barely known let alone mastered. Most people can do this even with the most basic knowledge and in fact most Open Source code is a of terrible quality. Mastering a language is not something one can achieve in a lifetime, like all skills we are only here for a finite time and as such we can only achieve a certain level of any skill and whilst some people would say they are a master of something, to truly master something you have to know everything and as human beings can't memorise everything it just won't happen. All you need to do is focus on a single language and learn all of the idioms and paradigms that exist for that language once you feel confident enough in its use then learn more esoteric things to do with the language and maybe look at how the language is actually implemented at a low level. These things as the minimum I would expect from someone that uses the term competent to describe their use of a language.

If you want to request user input in C you need to use the scanf() function which you aren't doing in this example. Until you actually request user input the program won't block for IO. The while loop is also unreachable as you aren't actually testing anything, you are only testing the negation of the constant EOF, you need to check this value against something. In short: You have to use scanf() to request user input and put it into a string. You need to check your logic in the while loop as testing for the negation of EOF (which will never be true) won't actually do anything.