Hello everyone.
I am a newbie in C programming and I have a quite challenging task to do.
I am supposed to write program where user enters a number (for example a number that user wants to get from cashpoint) and the program gives me as best solution as it's possible.
When user enters 215€, programs tells me it's 200€ and 10€ and 5€ (100€ and 100€ and 10 and 5 would be wrong, because it's not the biggest cash that user can get).
I would be really grateful if somebody helps me.
Thank you so much, Alisha.

It appears this is well done. There are even videos about this if you just need to get it done and not learn much.

Examples here.