Introduction - If you have any usage issues, please Google them yourself
This is a simple demo of how to evaluate mathematical expressions in text
format, including provision for variables and functions. The code consists of
three simple classes: 1) Calc- which does the main calculations, 2) Stack-
which is used to push and pop intermediate operators and numbers and 3)
Symbol Table. The symbol table is a collection of calc symbols, a type structure
consisting of various elements, including the expression name, function name,
and the final value of the expression The evaluation procedure is done in three
steps: 1) simplify the expression by removing all the elements within () and
storing them in subexpressions within the symbol table. 2) Each of these sub
expressions are then converted to RPN format (Reverse polar notation) and
evaluated 3) Finally, the main expression is converted to RPN and evaluated