How to resolve the algorithm File input/output step by step in the Common Lisp programming language

Published on 12 May 2024 09:40 PM
#Common lisp

How to resolve the algorithm File input/output step by step in the Common Lisp programming language

Table of Contents

Problem Statement

Create a file called   "output.txt",   and place in it the contents of the file   "input.txt",   via an intermediate variable. In other words, your program will demonstrate:

Oneliners that skip the intermediate variable are of secondary interest — operating systems have copy commands for that.

Let's start with the solution:

Step by Step solution about How to resolve the algorithm File input/output step by step in the Common Lisp programming language

Source code in the common programming language

(with-open-file (in #p"input.txt" :direction :input)
  (with-open-file (out #p"output.txt" :direction :output)
    (loop for line = (read-line in nil 'foo)
          until (eq line 'foo)
          do (write-line line out))))


(defconstant +buffer-size+ (expt 2 16))

(with-open-file (in #p"input.txt" :direction :input
                                :element-type '(unsigned-byte 8))
  (with-open-file (out #p"output.txt" 
                   :direction :output
                   :element-type (stream-element-type in))
    (loop with buffer = (make-array +buffer-size+
                                    :element-type (stream-element-type in))
          for size = (read-sequence buffer in)
          while (plusp size)
          do (write-sequence buffer out :end size))))

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