Hello, all.
I thought making a calculator would be a fairly simple practice exercise, but it's turning out more complicated than I had anticipated.
I don't want the user to be able to type a closing bracket if there isn't a matching opening bracket. I know how to search the string for specific characters, but I'm having trouble figuring out how to determine if there is an open parenthesis that needs to be closed.
Basically I want "(3+5)" to be possible, but "3+5)" to be impossible to type.

Thanks,
Teru