Linearsearch - LISP

Program:
(defun linsearch(n)
    (format t "~&<<LINEARSEARCH >>")
    (readn n)
    (format t "~&Enter the number to be searched:")
    (setf num (read))
    (setf flag 1)
    (do ((x 0 (+ x 1))) ((= x n))
        (if(= num (aref arr x))
            (setf flag 2)
        )
    )
    (if (= flag 2)
        (format t "Number present...")
        (format t "Number not present...")
    )
)
(defun readn(n)
    (setf arr (make-array n))
    (format t "~&Enter the ~d numbers:" n )
    (dotimes (x n t)
        (setf (aref arr x) (read))
    )
)

Output:
Break 4 [5]> (load 'ls.lsp)
;;  Loading file ls.lsp ...
;;  Loaded file ls.lsp
T
Break 4 [5]> (linsearch 5)
<<LINEARSEARCH >>
Enter the 5 numbers:1
2
3
4
5
Enter the number to be searched:4
Number present...
NIL
Break 4 [5]>