Programming Tutorials

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A Java program which takes contents of one file and sends the output to another file by adding line numbers to each line.

By: Ganesh Iyer in Java Tutorials on 2009年06月03日 [フレーム]

In this tutorial I will explain about File I/O functionality concept in JAVA. In this example, I have a file named compare.java which I want to write to a file named out.txt with the line numbers prefixed to each line.

/* Author   - Ganesh Iyer Contact No (0)9176148207
 Program   - 
 Written on - 03-06-2009 */
import java.io.*;
class Finputoutput{
  public static void main(String[] args) throws Exception
  {
   //Check for two arguments
   if(args.length != 2)
   {
   System.out.println(\"To execute the program
provide two parameters <INPUT> <SPACE> <OUTPUT> Files
\");
   System.exit(1);
   }
   String fname = args[0], wname = args[1], str;
   int counter=0;
   FileReader f = new FileReader(fname);
   BufferedReader in = new BufferedReader(f);
   FileWriter fw = new FileWriter(wname);
   while ((str=in.readLine()) != null)
   {
       counter++;
       fw.write(counter+\"
\"+str+\"\\n\");
       System.out.println(counter+\"
\"+str);
     }
     f.close();
     fw.close();
   }
}

To Execute - java Finputoutput <INPUT> <SPACE> <OUTPUT> Example - java Finputoutput compare.java out.txt

Output

1 class compare
2 {
3  public static void main(String[] args)
4  {
5    numcompare comparenum = new numcompare();
6    comparenum.threenumcompare();
7  }
8 }
9
10 class numcompare
11 {
12  void threenumcompare()
13  {
14
15     int a = 1;
16     int b = 2;
17     int c = 3;
18
19     if ((a>b)&&(c<a))
20     {
21       System.out.println(\"a
is gt b&c\");
22      }
23     else if ((b>a) &&
(c<b))
24      {
25       System.out.println(\"b
is gt a&c\");
26      }
27     else
28      {
29       System.out.println(\"c
is gt a&b\");
30     }
31   }
32 }

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