(write-line "———————————————————————————————————————————")
(write-line "Program to perform the arithmetic operations ")
(write-line "———————————————————————————————————————————")
(write-line "1.Addition")
(write-line "2.Subtraction")
(write-line "3.Multiplication")
(write-line "4.Division")
(write-line "———————————————————————————————————————————")
(princ "Enter your choice ")
(setq ch(read))
(terpri)(princ "Enter the 1st number ")
(setq a(read))
(terpri)(princ "Enter the 2nd number ")
(setq b(read))
(case ch
(1(format t "~%Addition Of ~d+~d=~d"a b (+ a b)))
(2(format t "~%Subtraction Of ~d-~d=~d"a b (- a b)))
(3(format t "~%Multiplication Of ~d*~d=~d"a b (* a b)))
(4(format t "~%Division Of ~d/~d=~d"a b (/ a b))))
(terpri)(princ "———————————————————————————————————————————")

kodingwindow@kw:~$ clisp kw.lisp
———————————————————————————————————————————
Program to perform the arithmetic operations 
———————————————————————————————————————————
1.Addition
2.Subtraction
3.Multiplication
4.Division
———————————————————————————————————————————
Enter your choice 4

Enter the 1st number 1

Enter the 2nd number 0

*** - /: division by zero

kodingwindow@kw:~$