Question regarding RPN and error detection

My task is too write a tree-based calculator program using RPN, that reads input from a file with commands delimited by ";".

I have done my data-flow charts, and tree diagram

Two potential issues occured to me, and after a few hours reading havent been able to resolve:

1 - ** [Resolved]**

The following was provided as an example line of input in the file:

Code:

`Sin(2pi*4.8)+exp(-pi)`

In order for me to use RPN on this task, doesn't the input have to be in RPN, something like:

Code:

` 2 pi 4.8 pi * * + exp`

*

2 - ** [Resolved]**

When error checking, while I have implemented an input validation, that can check for the right operators, numbers, and correct number of parentheses. Should I check for "Undefined" mathematical functions? Like 0/1. Or should I let them pass, and return undefined as an evaluation of the answer.

Would appreciate any form of advice.

*Or similar, not totally familiar with the RPN notation

**Edit: Question answered by Salem**