the first thing I made in java. basically the starter project for every new language.
Good work. You might like to split your logic up a bit more by creating functions that:
1. Get a number
2. Get the operator
3. Do the calculation
4. Handle the calling of the above functions in the right order
It's a rule of thumb that functions should do just one thing. This makes them more reusable and helps prevent too complicated logic. Your
openval function does several.