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Date: Mon, 02 Dec 1996 14:42:40 GMTServer: NCSA/1.4.2Content-type: text/html<HEADER><TITLE>CSE 415 Prog. Assignment 2</TITLE></HEADER><BODY><pre>CSE 415 Programming Project #2 due noon, Friday, April 26. (Use "Turnin" as directed). We discussed the following lisp program in class:(defun D (E x) (cond (( atom E) (cond ((equal E x) 1 ) ( T 0) )) ((or (equal (op E) '+ ) (equal (op E) '-)) `( ,(op E) ,(D (arg1 E) x) ,(D (arg2 E) x))) ((equal (op E ) '*) `(+ (* ,(arg1 E) ,(D (arg2 E) x) ) (* ,(arg2 E) ,(D (arg1 E) x ))) ))) This function allows only the operators, +, -, and * Add to the function, so that the operators, / and exp will be included. Note that exp is restricted so that the exponent is an integer. Run the function, with the call: (D '(/ (+ (exp x 2) 2) (* 5 x) ) 'x ) Then write a function, simplify ( E ) which will operate on the output of the D function and simplify the result, using only the following simplifications (where U is any expression or subexpression in the output of D). : (* U 0) -> 0 (* 0 U) -> 0 (exp U 1) -> U (* U 1) -> U (* 1 U) -> U (+ 0 U) -> U (+ U 0) -> U (- U 0) -> U (exp U 1) -> U (exp U 0) -> 1 [Note that more obvious simplifications could be made, but you should deal only with those above. eg Do not include the case, (- 0 U) or (+ 1 3) -> 4, etc. ] Run your functions with the call, (simplify (D E)), where E is the expression given in the above call of D. Use trace for both the D and simplify functions, so that your output will show the arguments passed and the values returned on each recursive call. Note: here are the handy functions to extract the operator and arguements from an expression: (defun op (E) (first E)) (defun arg1 (E) (second E)) (defun arg2 (E) (third E))</body>⌨️ 快捷键说明
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