입출력 (INPUT / OUTPUT)

;; INPUT/OUTPUT

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;; WITH-OPEN-FILE ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;; Opening file for output ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

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(defun get-tree-data ()

(with-open-file (stream "timber.txt")

(let* ((tree-loc (read stream))

(tree-table (read stream))

(num-trees (read stream)))

(format t "~&There are ~S trees on ~S." num-trees tree-loc)

(format t "~&They are: ~S" tree-table))))

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;; WITH-OPEN-FILE ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;; Opening file for output ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

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(defun save-tree-data (tree-loc tree-table num-trees)

(with-open-file (stream "timber.txt"

:direction :io

:if-exists :overwrite

:if-does-not-exist :create)

(format stream "~&~S~%" tree-loc)

(format stream "~&~S~%" tree-table)

(format stream "~&~S~%" num-trees)))

;; The text file is made in this location : C:\acl100express (Initial Location)

;; > (save-tree-data "The West Ridge"

;; '((45 redwood) (22 oak) (43 maple))

;; 110)

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;; Change the location to save the file?

(defun save-tree-data2 (tree-loc tree-table num-trees)

(with-open-file (stream "c:/temp/timber.txt" ;; You should use '/' instead of '\'. (UNIX System)

:direction :io

:if-exists :overwrite

:if-does-not-exist :create)

(format stream "~&~S~%" tree-loc)

(format stream "~&~S~%" tree-table)

(format stream "~&~S~%" num-trees)))

;; > (save-tree-data2 "The West Ridge"

;; '((45 redwood) (22 oak) (43 maple))

;; 110)

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;; Handling End Of File ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

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(defun read-my-file()

(with-open-file (stream "sample.txt")

(let ((contents (read-all-objects stream)))

(format t "~&Read ~3D objects from the file."

(length contents))

(contents))))

(defun read-all-objects (stream &optional eof-indicator)

(let ((result (read stream nil eof-indicator)))

(if (eq result eof-indicator) ;; same address?

nil

(cons result (read-all-objects stream)))))