Re: Is there a Bug in my code?
I would imagine that the block which says "Change Fish by Fish * Answer" (and the other similar ones) are adding Fish * Answer to the original value of Fish, meaning you would end up getting charged for one extra.
You probably don't want to use the same variables for storing the price of fish, chips etc. and setting the value of the fish, chips, etc. that have been bought - that's where I'd say you're going wrong.
Oh, and I'm not usually a language-police person, but the language in the question in that screenshot is a bit strong for posting here really...
Save the whales, feed the hungry, free the mallocs.