A numeric parser and evaluator for algebraic inorder expressions

The authors present the design of an arithmetic parsing and evaluation subroutine for the evaluation of multivariable inorder algebraic expressions. The method used is based on the parsing of an inorder algebraic expression into its equivalent postorder-reverse Polish form, through the use of a modified push down automaton. The evaluation subroutine is used to evaluate the resulting postorder expression, substituting given values for variables in the equation. Supporting algorithms are provided for the access and updating of a specified variable´s value