Consider arithmetic expressions like the ones described in the previous project. Allow ope...

Consider arithmetic expressions like the ones described in the previous project. Allow operands to be either integer values or variable names that are strings of letters. Design and implement an iterative algorithm that uses a stack to test whether an expression is legal in Lisp. Write a program that reads potential expressions and demonstrates your algorithm.

Each expression that your program reads can be split across several lines, which is the style used by typical

Lisp programmers. For example, the following expression is legal in Lisp:

(+ (- height)(* 3 3 4)(/ 3 width length)(* radius radius))

In contrast, the following expressions are illegal in Lisp: