HOW TO BECOME PROFICIENT IN C

So I claimed I was proficient in a number of languages on my resume, all of which I've barely used.

I think I can get away with some of it but I really think I need to know how to use C and Python well for the job. He said the job might require C# which is close enough to core C.

How do I become proficient with these languages in a week or so?

>>48
Ok, I did end up getting the program to work but I am still curious about the errors that guy mentioned. I understand all the problems except for the one I quoted (though I also don't know how to fix the scanf problem.)