I made the following changes: - Added a field to indicate the number of operands to the struct - Added ^ and % (forgot about these) - Fixed syntax errors - completed the functions. Now that I think about this, I could simplify the parser by writing a function int ArgCount(OperatorT op) ; That takes an op and returns the number of required operands. Had to fix my strip function because I forgot we were using + not add as an operation.