<p>Is there any way to interpret Reverse Polish Notation into "normal" mathematical notation when using either C++ or C#? I work for an engineering firm, so they use RPN occasionally and we need a way to convert it. Any suggestions?</p>

C# doesn't have built-in support for parsing Reverse Polish Notation (RPN).You'll need to write your own parser, or find one online.
There are dozens of tutorials for converting postfix form (RPN) to infix (Algebraic Equation). Take a look at
this
, maybe you'll find it useful and you can try to ‘reverse engineer’ it to convert postfix expressions to infix form, keeping in mind that there can be multiple infix notations for a given postfix one. There are very few useful examples that actually discuss converting postfix to infix. Here’s a 2-part entry that I found very useful. It also has some pseudo code:
PostFix to Infix: converting RPN to algebraic expressions
Postfix to infix, part 2: adding the parentheses