File input/output is part of Short Circuit's Console Program Basics selection.
Task

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:

   how to read from a file into a variable
   how to write a variable's contents into a file


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




#lang racket
(define file-content
  (with-input-from-file "input.txt"
    (lambda ()
      (let loop ((lst null))
        (define new (read-char))
        (if (eof-object? new)
            (apply string lst)
            (loop (append lst (list new))))))))
 
(with-output-to-file "output.txt"
  (lambda ()
    (write file-content)))