Die Herausforderung:

Geben Sie Text aus einer Datei ein und geben Sie ihn in eine andere aus. Die Lösung sollte eine vollständige, funktionierende Funktion sein.

_{Hinweis: Dies ist eine Code-Trolling- Frage. Bitte nehmen Sie die Frage und / oder die Antworten nicht ernst. Mehr Infos hier .}

C

Der springende Punkt bei der Verwendung mehrerer Programmiersprachen ist, dass Sie das richtige Werkzeug für den Job verwenden müssen.
In diesem Fall möchten wir Bytes von einer Datei in eine andere kopieren.
Während wir etwas Phantasievolles wie Bash oder Ruby gebrauchen oder die Kraft von ASM nutzen könnten, brauchen wir etwas Schnelles, Gutes mit Bits und Schnelles.
Die offensichtliche Wahl ist C.
Die EINFACHSTE Art, dies zu tun, wäre wie folgt:

#include <stdio.h>
#define THEORY FILE
#define AND *
#define PRACTICE myfile1
#define SOLUTIONS myfile2
#define ARE fopen
#define IMPORTANT "r"
#define BAD "w"
#define LOL fclose
#define PLEASE fgetc
#define HELP fputc
#define ME return
#define NEVER for
#define SURRENDER !=
#define VERY filename1
#define NOT filename2
#define _ 1

int copyFile(char* filename1, char* filename2)
{
  THEORY AND PRACTICE = ARE (VERY, IMPORTANT);
  THEORY AND SOLUTIONS = ARE (NOT, BAD);
  NEVER (;_;)
  {
    HELP(PLEASE(PRACTICE),SOLUTIONS);
  }
  ME _SURRENDER_;
}

Das ist böse, weil es Müll über Dinge wie Cygwin liest, für Anfänger komplett chinesisch ist, ihn erschreckt, wenn er merkt, dass es ein Hilferuf ist, und offensichtlich, weil C.

sh

I like the simplicity of this one.

echo File1.txt > File2.txt

Really only works properly if File1.txt contains "File1.text"...

AutoHotKey

WinActivate, file1.txt
SendInput ^a^c
WinActivate, file2.txt
SendInput ^a^v^s

You must first open the files in notepad or some other text editor that makes the window names start with the file names. Then it copies the contents of file1 to the clipboard (literally, using ctrl+c), and pastes it into file2, overwriting anything currently in it, and saves.

Solves the problem, but in a very inconvenient and pretty useless fashion. It would probably by easier to just copy and paste manually.

As everyone knows, perl is very good for manipulating files. This code will copy the contents of one file to another, and will do so with extra redundancy for good measure.

#Good perl programs always start thusly
use strict;
use warnings;

my $input_file  = 'File1.txt';
my $output_file = 'File2.txt';
open(my $in, '<', $input_file) or die "Couldn't open $input_file $!";

my $full_line = "";
while (my $line = <$in>) {
    #Get each letter one at a time for safety, 
    foreach my $letter (split //, $line) {
        #You could and should add validity checks here
        $full_line .= $letter;

        #Get rid of output file if it exists!  You are replacing it with
        # new content so it's just wasting space.
        unlink $output_file if (-e $output_file);

        #Write data to new file
        open(my $out, '>', $output_file) or die "Couldn't open $output_file $!";
        print {$out} $full_line;
        close($out);
    }
}

To be safe, test this out on a small file at first. Once you are convinced of its correctness you can put it into production for use on very large files without worry.

C#

In order to achieve this, you must make sure to do several things:

1. Read string from file
2. Download Microsoft File IO and String Extension for Visual Studio
3. Remove viruses from string ("sanitize")
4. Write file to path
5. Delete and reload cache

Here's the code:

static void CopyTextFile(string path1, string path2)
    {
        try
        {
            FileStream fs = new FileStream(path1, FileMode.OpenOrCreate); //open the FTP connection to file
            byte[] file = new byte[fs.Length];
            fs.Read(file, 0, file.Length);
            string makeFileSafe = Encoding.UTF32.GetString(file);

            using (var cli = new WebClient())
            {
                cli.DownloadData(new Uri("Microsoft .NET File IO and String Extension Package")); //get MS package
            }

            fs.Dispose();

            File.Create(path2);
            StreamReader read = new StreamReader(path2);
            read.Dispose(); //create and read file for good luck

            var sb = new StringBuilder();
            foreach (char c in path1.ToCharArray())
            {
                sb.Append(c);
            }

            string virusFreeString = sb.ToString(); //remove viruses from string

            File.WriteAllText(path2, virusFreeString);
            File.Delete(path1);
            File.WriteAllText(path1, virusFreeString); //refresh cache
        }
        catch
        { 
            //Don't worry, exceptions can be safely ignored
        }
    }

In four simple steps:

1. Print the file. You can use the lpr command for this.
2. Mail the printouts to a scanning service. (You will need postage for this).
3. The scanning service will scan the printouts and do OCR for you.
4. Download to the appropriate file location.

Java

A lot of people find it useful to attempt to use regular expressions or to evaluate strings in order to copy them from one file to another, however that method of programming is sloppy. First we use Java because the OOP allows more transparency in our code, and secondly we use an interactive interface to receive the data from the first file and write it to the second.

import java.util.*;
import java.io.*;

public class WritingFiles{



 public static void main(String []args){
    File tJIAgeOhbWbVYdo = new File("File1.txt");
    Scanner jLLPsdluuuXYKWO = new Scanner(tJIAgeOhbWbVYdo);
    while(jLLPsdluuuXYKWO.hasNext())
    {
        MyCSHomework.fzPouRoBCHjsMrR();
        jLLPsdluuuXYKWO.next();
    }
 }
}

class MyCSHomework{
    Scanner jsvLfexmmYeqdUB = new Scanner(System.in);
    Writer kJPlXlLZvJdjAOs = new BufferedWriter(new OutputStreamWriter( new  FileOutputStream("File2.txt"), "utf-8"));
    String quhJAyWHGEFQLGW = "plea";
   String LHpkhqOtkEAxrlN = "f the file";
   String SLGXUfzgLtaJcZe = "e nex";
   String HKSaPJlOlUCKLun = "se";
   String VWUNvlwAWvghVpR = " ";
   String cBFJgwxycJiIrby = "input th";
   String ukRIWQrTPfqAbYd = "t word o";
   String  CMGlDwZOdgWZNTN =   quhJAyWHGEFQLGW+HKSaPJlOlUCKLun+VWUNvlwAWvghVpR+cBFJgwxycJiIrby+SLGXUfzgLtaJcZe+ukRIWQrTPfqAbYd+LHpkhqOtkEAxrlN;
    public static void fzPouRoBCHjsMrR(){
        System.out.println(CMGlDwZOdgWZNTN);
        kJPlXlLZvJdjAOs.write(jsvLfexmmYeqdUB.next());
    }



}

In theory (I haven't tested it) this makes the user manually input the content of the first file (word by word) and then writes it to the second file. This response is a play on the ambiguity of the question as to what it means by "input text from one file," and the crazy variable names (generated randomly) were just for some extra fun.

sh

Like @Shingetsu pointed out, one has to use the right tool for the right job. Copying the content from one file to another is an old problem, and the best tool for such file-management tasks is using the shell.

One shell command that every programmer has to familiarise themself with is the common tac command, used to tack the content of files together, one after another. As a special case of this, when only one file is passed in it is simply spit out as-is again. We then simply redirect the output to the appropriate file:

tac inputfile.txt >outputfile.txt

Simple and to-the-point, no tricks!

Perl

Antivirus included.

#!/usr/bin/perl -w
use strict;
use warnings;

print "Copy the text of the file here: (warning: I can't copy files with newlines):\n";
my $content = <STDIN>;

print "\n\nPlease wait, removing viruses...";
my @array = split(//,"$content");
my @tarray;

foreach my $item (@array)
{
    if ($item ne "V" && $item ne "I" && $item ne "R" && $item ne "U" && $item ne "S")
    {
        push(@tarray, $item);
    }

}

print "\n\nNow copy this into the target file:\n";

foreach my $item (@tarray){ print "$item"};

Windows Batch

(because you gotta have this supposedly "dead" language ;-)

@echo off
setlocal enabledelayedexpansion
for %%I in ('type %1') do set this=!this!%%I
echo !this!>%2 2>nul

You simply call this as copy.bat file1.txt file2.txt (or whatever files you want)

If only it would keep line breaks...

Linq

Efficiency is not important, correctness is. Writing in a functional style results in more clear and less error-prone code. If performance does turn out to be a problem, the last ToArray() line can be omitted. It's better to be lazy anyway.

public void CopyFile(string input, string output)
{
    Enumerable
        .Range(0, File.ReadAllBytes(input).Length)
        .Select(i => new { i = i, b = File.ReadAllBytes(input)[i] })
        .Select(ib => {
            using (var f = File.Open(output, ib.i == 0 ? FileMode.Create : FileMode.Append))
                f.Write(new byte[] { ib.b }, 0, 1);
            return ib; })
        .ToArray();
}

Smalltalk

There is a library yet ported to several Smalltalk dialects (Visualworks, Gemstone Squeak/Pharo, ...) named Xtreams that makes this task more than easy.

FileStream would be as simple as 'foo' asFilename reading and 'bar' asFilename writing for example in Visualworks, but are dialect specific.
For this reason I demonstrate the algorithm with dialect neutral internal Streams instead.
A good idea could be to process each byte code in increasing order:

| input |
input := 'Hello world' asByteArray reading.
^((ByteArray new writing)
    write: ((0 to: 255) inject: ByteArray new reading into: [:outputSoFar :code |
        | nextOutput |
        nextOutput := ByteArray new writing.
        ((input += 0; selecting: [:c | c <= code]) ending: code inclusive: true) slicing do: [:subStream |
            | positionable |
            positionable := subStream positioning.
            nextOutput write: (outputSoFar limiting: (positionable ending: code) rest size).
            nextOutput write: (positionable += 0; selecting: [:c | c = code])].
        nextOutput conclusion reading]);
    conclusion) asString

Of course, it is also possible to process in random order, but i'm afraid that it makes the code a bit too compact:

| input output |
input := 'Hello world' asByteArray reading.
output := ByteArray new writing.
(0 to: 255) asArray shuffled do: [:code |
        output += 0.
        (input += 0; ending: code inclusive: true) slicing do: [:subStream |
            | positionable |
            positionable := subStream positioning.
            output ++ (positionable += 0; rejecting: [:c | c = code]) rest size.
            output write: (positionable += 0; selecting: [:c | c = code])]].
^output conclusion asString

EDIT

Ah stupid me, I didn't saw the log2 solution:

| input output |
input := 'Hello world' asByteArray reading.
(output := ByteArray new writing) write: (input collecting: [:e | 0]).
output := (0 to: 7) asArray shuffled inject: output into: [:outputSoFar :bit |
        (ByteArray new writing)
            write:
                (((input += 0; collecting: [:e | e >> bit bitAnd: 1]) interleaving: outputSoFar conclusion reading) 
                    transforming: [ :in :out | out put: in get << bit + in get]);
            yourself].
^output conclusion asString

BASH

on terminal #1 with the IP, 192.168.1.2

nc -l 8080 | gpg -d > mydocument.docx

on terminal #2 with the IP, 192.168.1.3

gpg -c mydocument.docx | nc 192.168.1.2 8080

This will encrypt and send mydocument.docx, using nc and gpg, over to terminal #1 You will have to type the password on terminal #2, then on terminal #1

C++

This is somewhat based on Shingetsu's answer, but I couldn't resist. It is fully functioning, but no student would submit it to their teacher (I hope). If they are willing to analyze the code, they will be able to solve their problem:

#include <iostream>
#include <fstream>
#include <string>
using namespace std;
#define SOLVE ifs
#define IT >>
#define YOURSELF ofs

ifstream& operator IT(ifstream& ifs, ofstream& ofs) {
  string s;
  SOLVE IT s;
  YOURSELF << s;
  return ifs;
}

void output(ofstream& ofs, ifstream& ifs) {
  while (ifs) {
    SOLVE IT YOURSELF;
    ofs << ' ';
  }
}

int main() try {

  ofstream ofs("out.txt");
  ifstream ifs("in.txt");

  output(ofs, ifs);

  return 0;
}
catch (exception& e) {
  cerr << "Error: " << e.what() << endl;
  return 1;
}
catch (...) {
  cerr << "Unknown error.\n";
  return 2;
}

Python

Inputs text from file1.txt and outputs it to file2.txt

It's complete and "working". No one said anything about writing the input as it is. All input characters appear in the output. "getchar" is the trolling part.

from random import choice as getchar

f1 = open("file1.txt")
s1 = []
for line in f1:
    for char in line:
        s1.append(str(char))
s2 = ''
while len(s1) > 0:
    x = getchar(s1)
    s2 += x
    s1.remove(x)
f2 = open("file2.txt" , 'w')
f2.write(s2)

Mathematica, 44 characters

Implementation

f = (BinaryWrite[#2, BinaryReadList@#]; Close@#2) &

Execution

f["one file", "another"]

Check

check = Import[StringJoin["!diff \"", #, "\" \"", #2, "\" 2>&1"], "Text"] &;
check["one file", "another"]

DELPHI / PASCAL ( copy from f1.txt to f2.txt )

program t;

{$APPTYPE CONSOLE}

uses
  classes;

var a : TStringlist;
begin
   a:=TStringlist.Create;
   a.LoadFromFile('e:\f1.txt');
   a.SaveToFile('e:\f2.txt');
   a.Free;
end.

MASM

I'm certainly not an assembly expert, but below is my little snippet:

include \masm32\include\masm32rt.inc

.code

start:
call main
inkey
exit

main proc
LOCAL hFile :DWORD  
LOCAL bwrt  :DWORD 
LOCAL cloc  :DWORD 
LOCAL flen  :DWORD  
LOCAL hMem  :DWORD  

.if rv(exist,"out.txt") != 0  
  test fdelete("out.txt"), eax 
.endif

mov hFile, fopen("source.txt")
mov flen, fsize(hFile)
mov hMem, alloc(flen)   
mov bwrt, fread(hFile,hMem,flen)  
fclose hFile   

invoke StripLF,hMem

mov hFile, fcreate("out.txt") 
mov bwrt, fwrite(hFile,hMem,flen)   
fclose hFile   

free hMem   

ret

main endp
end start

C++

Did you notice the "complete, working function" bit? Anyway, here is my answer:

#include <stdlib.h>
int main(void)
{
  system("echo < input > dest");
}

Lua

io.read()

Run with an input file containing text from one file and output it to another. Solution should be a complete, working function..

PHP

function copyFile($input, $output) 
{
    return file_put_contents($output, file_get_contents($input));
}

#!/bin/sh

contents=`< $1` ; echo "$contents" > $2

Looks reasonable, but rather inefficient if the file is large.

Works fine on ASCII files except when the input file contains -n, -e or -E. (Because these are interpreted as arguments by echo.)

Does not produce the correct output for all (most) binary files.

(Using printf "%s" "$contents" > output under /bin/bash works a little better, but that still drops NULL bytes.)

Oh and of course it doesn't work for filenames_containing_spaces. But such files are illegal under UNIX%20policy anyway.