Compiling with obvious errors

[Univcplus]

So I am coding and obviously I build occasionally to make sure my program runs. I got suspicious since something that I was almost sure wouldn't work. worked. so I then typed a random letter a to try and get an error, but it still built and ran without an error.
I was using a struct.word at the time.

[SakurasouBusters]

What program are you talking about?

[Duthomhas]

Without an example of what you are doing it is impossible to comment intelligently.