File input/output

File input/output
You are encouraged to solve this task according to the task description, using any language you may know.

In this task, the job is to create a file called "output.txt", and place in it the contents of the file "input.txt".

C

Compiler: GCC 4.1.2

#include <stdio.h>

int main(int argc, char **argv) {
  FILE *in, *out;
  int c;

  in = fopen("input.txt", "r");
  if (!in) {
    fprintf(stderr, "Error opening input.txt for reading.\n");
    return 1;
  }

  out = fopen("output.txt", "w");
  if (!out) {
    fprintf(stderr, "Error opening output.txt for writing.\n");
    return 1;
  }

  while ((c = fgetc(in)) != EOF) {
    fputc(c, out);
  }

  return 0;
}

C#

Platform: .NET Language Version: 1.0+

   using System;
   using System.IO;
 
   namespace FileIO
   {
       class Program
       {
           static void Main(string[] args)
           {
               if (File.Exists("input.txt"))
               {
                   TextReader tr = File.OpenText("input.txt");
                   TextWriter tw = new StreamWriter(File.OpenWrite("output.txt"));

                   while (tr.Peek() != -1)
                   {
                       string line = tr.ReadLine();

                       tw.WriteLine(line);
                   }

                   tw.Close();
                   tr.Close();
               }
               else
               {
                   Console.WriteLine("Input File Missing.");
               }
           }
       }
   }

C++

Compiler: GCC 3.4.2

#include <iostream>
#include <fstream>
#include <string>
int main() {
    string line;
    ifstream input ( "input.txt" );
    ofstream output ("output.txt");
    if (output.is_open()) {
        if (input.is_open()) {
            while (! input.eof() ) {
                getline (input,line);
                output << line << endl;
            }
        input.close();
        }
        else {
            cout << "input.txt cannot be opened!\n";
        }
    output.close();
    }
    else {
        cout << "output.txt cannot be written to!\n";
    }
    return 0;
}

Java

Compiler: GCJ 4.1.2

Simple version; files are closed by OS when the program finishes

import java.io.*;

public class FileIODemo {
  public static void main(String[] args) {
    try {
      FileInputStream in = new FileInputStream("input.txt");
      FileOutputStream out = new FileOutputStream("ouput.txt");
      int c;
      while ((c = in.read()) != -1) {
        out.write(c);
      }
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}

This version closes both files after without OS intervention

import java.io.*;

public class FileIODemo2 {
    public static void main(String args[]) {
        InputStream in = null;
        OutputStream out = null;
        try {
            in = new FileInputStream("input.txt");
            out = new FileOutputStream("output.txt");
            int c;
            while ((c = in.read()) != -1) {
                out.write(c);
            }
        }
        catch (Exception e) {
            System.err.println("Exception while trying to copy: "+e);
            e.printStackTrace(); // stack trace of place where it happened
        }
        finally { // guaranteed to be reached, whatever the exceptions
            try {
                if (in != null) in.close();
                if (out != null) out.close();
            } // close() may also launch exception... yes, Java is like this
            catch (IOException ioe) {
               System.err.println("Exception closing files: "+ioe);
            } 
        }
    }
}

Perl

Interpreter: Perl 5.8.8

#!/usr/bin/perl -w

open INPUT, "<input.txt";
open OUTPUT, ">output.txt";

while ( <INPUT> ) {
  print OUTPUT $_;
}

PHP

Interpreter: PHP 4

 <?php
 
 if (!$in=fopen('input.txt','r')) {
 	die('Could not open input.txt!');
 }
 
 if (!$out=fopen('output.txt','w')) {
 	die('Could not open output.txt!');
 }
 
 while(!feof($in)) {
 	$data = fread($in,512);
 	fwrite($out,$data);
 }
 
 fclose($out);
 fclose($in);
 ?>
 

Interpreter: PHP 5

 <?php
 if( $contents = file_get_conents('input.txt') ){
 	if( !file_put_contents('output.txt') ) echo('could not write output file');
 }else{
 	echo('could not open input file');
 }
 ?>

mIRC

Compiler: mIRC

 alias Write2FileAndReadIt {
 .write myfilename.txt Goodbye Mike!
 .echo -a Myfilename.txt contains: $read(myfilename.txt,1)
 }

Python

Interpreter: Python 2.4

In short form:

 open("output.txt", "w").writelines(open("input.txt"))

With proper closing and exception-handling:

inputFile = open("input.txt","r")
try:
  outputFile = open("output.txt", "w")
  try:
    outputFile.writelines(inputFile)
  finally:
    outputFile.close()
finally:
  inputFile.close()

TCL

Interpreter: tclsh, eTcl, wish, tixwish

set in [open "input.txt" r]
set out [open "output.txt" w]
puts -nonewline $out [read $in]
close $in
close $out

Other File I/O:

#open file for writing
set myfile [open "README.TXT" w]
#write something to the file
puts $myfile "This is line 1, so hello world...."
#close the file
close $myfile

#open file for reading
set myfile [open "README.TXT" r]
#read something from the file
gets $myfile mydata
#show what was read from the file
#should print "This is line1, so hello world...."
puts $mydata
#close the file
close $myfile

UNIX Shell

Interpreter: Bourne Shell Operating System: UNIX

#!/bin/sh

while read a; do
    echo "$a"
done <input.txt >output.txt