reverse the text file and write

[brando brandido]

hello i am having trouble how to reverse the given text file word by word.

this is a sample text file

"Ye-es. Pretty well - some poetry", Alice said doubtfully.
A long time ago in a galaxy far, far away...
It was a dark and stormy night; the rain fell in torrents ..
Ab4cd efg hijklm1 5nop qrs-tuvw xyz.

need to display the text file and write it in a new file in reverse word by word.

so give the about input

the new file in reverse will look like this

“eY – se. ytterp llew – emos yrteop”, ecilA dias ylluftbuod.
A gnol emit oga ni a yxalag raf, raf yawa…
tI saw a krad dna ymrots thgin; eht niar llef ni stnerrot..
dc4bA gfe 1mlkjih pon5 srq-wvut zyx

this is what i got so far, i am only able to display the text file

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

public class reverseString
{
	public static void main (String [] args)throws IOException
	{
		FileReader fr = new FileReader("reverse_input.txt");
		FileWriter fw = new FileWriter("reverse_output.txt");
		BufferedReader janus = new BufferedReader(fr);
		
		String data;
		String reverse;
		
		while ((data = janus.readLine()) != null) 
	    System.out.println (data);
	    
	   
	  
	  
               
	}
}

[Pavan Kumar Dittakavi]

You are almost there. Just reverse the string that you have got into the 'data' string object and write it to the file.

Thanks,
Pavan.

[Manoj Kumar Jain]

Pavan Kumar Dittakavi wrote:You are almost there. Just reverse the string that you have got into the 'data' string object and write it to the file.

No, the problem doesn't say that he need to reverse the complete line, rather the problem is that he need to reverse the each word.
He can do it by parsing the line by whitespace and then reverse each word but he should take care of this

"far," should be revresed like "raf," not ",raf"

so he need to take care of punctuation marks as well.

I would like to suggest you to parse the line with whitespace that you are getting in "data" this will give you the list of words in a single line.
now process each word in the list to be reversed, you need to avoid the (, . ? ... etc) if these are appearing in the end of the word

[Alex Theedom]

A possible solution is to read a line of text from the file, use a regular expression to match on a word, reverse the word and write back to the file. Here is my solution:

public class ReverseText {

	public static void main(String args[]){
		
		throw new IfCampbellSeesThisCodeHeWillDeleteItException("Thank you for noticing, Joanne :-)");
	}	
}

As you cannot see line 18 contains a . . .

I hope this helps.

[Joanne Neal]

Alex Theedom wrote:I hope this helps.

Actually it doesn't help at all. As it says at the top of the Beginner's Forum

We're all here to learn, so when responding to others, please focus on helping them discover their own solutions, instead of simply providing answers.

[Campbell Ritchie]

Pencil and paper. Write down how you intend to identify words, and how to print them backwards. I think “Ye - es” will be almost impossible to identify as a word.
Once you have got it written down, and reduced it to words of one syllable, you will find it very easy ot convert to code.

And thank you for noticing the straight answer, Joanne. I have altered it slightly.

[Campbell Ritchie]

I see the example you gave reverses “Ye - es” as two words.

[Pablo Reyes]

When you have the line read in data, split it with the split() method using a space as a separator. Then, loop through the array and reverse each element and print it.

FileReader fr = new FileReader("reverse_input.txt");  
FileWriter fw = new FileWriter("reverse_output.txt");  
BufferedReader janus = new BufferedReader(fr);  
          
String data;  
          
while ((data = janus.readLine()) != null){
    String[] words = data.split(" ");
    for(String a: words){
        StringBuilder builder=new StringBuilder(a);
        System.out.print(builder.reverse().toString()));
    }  
}

Maybe not the most efficient solution, but it should work (haven't tested it)

[Joanne Neal]

Pablo Reyes wrote:it should work

No it won't for the reason already pointed out earlier in this thread by Manoj Kumar Jain

[brando brandido]

@Pablo Reyes

it wont work because you will end up with word like this .se-eY" the right reverse should look like this “eY – se.

this is what i did

import java.util.*;

    import java.io.*;
public class reverse {
  public static void main (String [] args)throws IOException {



			FileReader fr = new FileReader("sales.txt");
            BufferedReader fw = new BufferedReader(fr);
            String data = janus.readLine();


				StringTokenizer tokens = new StringTokenizer(data, " .,\"-");
				while (tokens.hasMoreTokens()){
								String ss = tokens.nextToken();
								for (int i = ss.length() - 1; i>=0; i--) {

								char dd = ss.charAt(i);
								System.out.print(dd);
								}
								System.out.print(" ");


					}

				}
}

i am able to read the first line only, i dont know how to get the next text line

the output of the above code is

eY se ytterP llew emos yrteop ecilA dias ylluftbuod 

my plan is to pick each word and arrange them later to get the desired output in the reverse_output.txt file
so i will pick the first two word and insert - between them, and " before them. and the the rest too.

i probably will use indexOf and substring? but don't know where to start, need idea or example to proceed.

[Campbell Ritchie]

Still not quite right; you are missing out the punctuation.

I think you have been given a task far too difficult for your level of experience. I think you would use a regular expression and print what was matched and reverse what was skipped. But I can’t think offhand what the code would look like.

[Manoj Kumar Jain]

I can think of one of the solution to this problem.
As I said earlier first you need to parse the complete line with space to get a list of the words.
now take each word and process it character by character.

if ((char >=65 &&char <=90 )||(char >=97&&char<=122)||(c >=48&&c<=57))

holds true then add the characters to an string and reverse them till you find a special char.
I am not able to explain it very well let me paste some sample code here.

public static void main(String[] args) {
		String str = "\"ye-es.";
		System.out.println(str);
		String first = "";
		String second = "";
		for (int i = 0; i < str.length(); i++) {

			char c = str.charAt(i);
			if ((c >= 65 && c <= 90) || (c >= 97 && c <= 122)
					|| (c >= 48 && c <= 57)) {
				second = c + second;
			} else {

				first = first + second + c;
				second = "";
			}
		}
		System.out.println(first);

	}

This seems fine to me...
if you want to add spaces at both side of - symbol you can add that too.
Hope I am not violating rules and Campbell will not delete the code.

[brando brandido]

@Manoj Kumar Jain

how am i suppose to call the 2nd line of text? and so on?

[Campbell Ritchie]

Manoj Kumar Jain wrote: . . .

if ((char >=65 &&char <=90 )||(char >=97&&char<=122)||(c >=48&&c<=57))

. . .

Good grief! There are at least 4 errors in that line alone!

1: It won’t compile.

2: Poor formatting; you should have spaces around all binary operators.

3: Minor error: use of decimal numbers rather than hex.

4: Use of number literals at all. If you must use literals, why don’t you use character literals?

5: Not looking in the Character class where you would have found a method which does all that for you.

So that’s 5

And why do you need to look for spaces if you use that technique?

Actually, if you are going to use that technique, you can put the individual letters into a StringBuilder in the appropriate location. Remember which characters require you to increase your insertion index and which don’t. Much easier.
For a second line, you get your file reading classes to read the next line. Just append String lineEnd = System.getProperty("line.separator") at each line and increase your index by lineEnd.length(). Don’t use "\n" or similar. I think I have spelt the name of the property correctly; you will have to check that you get new lines rather than “null” printing out.

[brando brandido]

using the hint given by Manoj Kumar Jain

i gt it

import java.util.*;
import java.io.*;
public class reverse {

    public static void main(String[] args) throws IOException {
        FileReader fr = new FileReader("reverse_input.txt");
        BufferedReader fw = new BufferedReader(fr);

        FileWriter out = new FileWriter("reverse_output.txt");
        BufferedWriter br = new BufferedWriter(out);

        String data;
       

        while ((data = fw.readLine()) != null) {

            String first = "";
            String second = "";


            for (int i = 0; i < data.length(); i++) {

                char c = data.charAt(i);
                if (((c >= 65 && c <= 90) || (c >= 97 && c <= 122) || (c >= 48 && c <= 57))
                        && i < data.length() - 1) {
                    second = c + second;
                }

                else {

                    first = first + second + c;
                    second = "";
                }
            }

            br.write(first + "\r\n");
            System.out.print(first + "\r\n");

        }
        br.close();



    }

    
}

but i don't like it,

i want to use tokenizer please....

[Winston Gutkowski]

brando brandido wrote:i want to use tokenizer please....

If you're talking about StringTokenizer, my advice is: DON'T. It is a legacy class and it's use, particularly in new code, is discouraged (have a look at the documentation).

You can do exactly the same things (and more) with String.split().

Winston

[brando brandido]

yes but our teacher wants us to use stringtokenizer.

so i must use it.

[Rob Spoor]

In this case I think StringTokenizer is a better solution than String.split because you need the tokens you split on as well. With String.split these are discarded.

An alternative I would use is directly use Pattern and Matcher. In semi pseudo code:

Pattern pattern = Pattern.compile(letters and digits, Pattern.CASE_INSENSITIVE);
Matcher matcher = pattern.matcher(line);
StringBuffer sb = new StringBuffer();
while (matcher.find())
{
    String match = matcher.group();
    String reversed = reverse match;
    matcher.appendReplacement(sb, reversed);
}
matcher.appendTail(sb);
String result = sb.toString();

[Winston Gutkowski]

brando brandido wrote:yes but our teacher wants us to use stringtokenizer.
so i must use it.

You're in a classroom, not the army. It may be worth pointing out the relevant paragraph in StringTokenizer to your teacher (it's near the end of the main section and starts with the phrase "StringTokenizer is a legacy class..."), and asking him/her whether it would be permissible to use String.split() or, as Rob suggests: Pattern and Matcher.

It's quite possible that the curriculum was written a while ago, and that he/she is unaware of the new recommendations (although they're not that new).

If I were your teacher, I might even give you some brownie points.

Winston

[Amit Goda]

A possible way according to me is, split contents of variable data at each whitespace character. You'll get an Array. And now traverse through the each word in array and use charAt(int index) method of String to reverse the word and store it in a String. Similarly append all the words and your output will be ready. .

Hope it helps!

[Manoj Kumar Jain]

Campbell Ritchie wrote:

Manoj Kumar Jain wrote: . . .

if ((char >=65 &&char <=90 )||(char >=97&&char<=122)||(c >=48&&c<=57))

. . .

Good grief! There are at least 4 errors in that line alone!

1: It won’t compile.

This code is compiling and running fine.. I pasted code here after running it..

[Manoj Kumar Jain]

oh got it ! Actually I type that line myself and completed it by editing two times.... but code was working fine....

[Jeff Verdegan]

Manoj Kumar Jain wrote:oh got it ! Actually I type that line myself and completed it by editing two times.... but code was working fine....

Did you notice his other points, that had nothing to do with whether it compiles or runs?

[Manoj Kumar Jain]

Amit Goda wrote:A possible way according to me is, split contents of variable data at each whitespace character. You'll get an Array. And now traverse through the each word in array and use charAt(int index) method of String to reverse the word and store it in a String. Similarly append all the words and your output will be ready. .

Hope it helps!

Welcome to the Ranch !
Please read the thread from OP. Requirement is quite different, its not just to reverse each word.

[Manoj Kumar Jain]

Jeff Verdegan wrote:

Manoj Kumar Jain wrote:oh got it ! Actually I type that line myself and completed it by editing two times.... but code was working fine....

Did you notice his other points, that had nothing to do with whether it compiles or runs?

Yes Jeff I noticed others points as well. He is quite correct and these points should be imbibed..

[Winston Gutkowski]

Manoj Kumar Jain wrote:Yes Jeff I noticed others points as well. He is quite correct and these points should be imbibed..

I thought it was pints that should be imbibed.

Winston

[Manoj Kumar Jain]

Winston Gutkowski wrote:

Manoj Kumar Jain wrote:Yes Jeff I noticed others points as well. He is quite correct and these points should be imbibed..

I thought it was pints that should be imbibed.

Winston

sorry, couldn't get you ?

[Jeff Verdegan]

Manoj Kumar Jain wrote:

Winston Gutkowski wrote:

Manoj Kumar Jain wrote:Yes Jeff I noticed others points as well. He is quite correct and these points should be imbibed..

I thought it was pints that should be imbibed.

Winston

sorry, couldn't get you ?

"Imbibe" means drink. In American and British English, we don't talk about "imbibing points". On the other hand a pint (of beer), is perfect for imbibing. Pint, point. Only a one-letter difference.

[Manoj Kumar Jain]

oh, so he is playing with words...
anyways, I hope my english will also improve along with JAVA here

[Ryan Alfeche]

hope this one will help..

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

public class  Reverse{
	public static void main (String [] args) throws IOException{
		FileReader fr = new FileReader("reverse_input.txt");
		FileWriter fw = new FileWriter("reverse_output.txt");
		
		BufferedReader ryan = new BufferedReader(fr);
		String data = ryan.readLine();		
		while(data != null){
			String get = gdata(data);
			System.out.println(get);
			fw.write(get+"\r\n");
			data = ryan.readLine();
		}

		fr.close();
		fw.close();
	}
	
	public static String gdata(String d){
		StringTokenizer st = new StringTokenizer(d, "\"-.,;", true);
		String g = "";
		while(st.hasMoreTokens()){
			String s = st.nextToken();
			int count = s.length();
			if(count == 1){
				g += s;
			}
			else{
				StringTokenizer st2 = new StringTokenizer(s, " ", true);
				while(st2.hasMoreTokens()){
					String s2 = st2.nextToken();
					int count2 = s2.length();
					for(int i = 1; i <= count2; i++){
						char c = s2.charAt(count2-i);
						g += c;
					}
				}
			}
		}
		return g;
	}
}

Just edit this code if you like.. hehe

[Jeff Verdegan]

Ryan Alfeche wrote:hope this one will help..

No, it is not helpful. Handing somebody the answer rather than nudging them in the right direction so that they can figure it out for themselves simply denies them the opportunity to learn and encourages intellectual dishonesty.

This site is NotACodeMill(⇐link), and as it says right on the topic page, "We're all here to learn, so when responding to others, please focus on helping them discover their own solutions, instead of simply providing answers."

[brando brandido]

Thank you all for all the replies, suggestions and support

i actually gt it too.

This is my own version. with comments and proper programming.

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

public class Reverse {
	//line separator. Used system property to prevent cross-OS issues (\n or \r\n)
	private static final String NEW_LINE_SEPARATOR = System.getProperty("line.separator");	
	/**
	 * @param args
	 */
	public static void main(String[] args) throws IOException, ArrayIndexOutOfBoundsException {
		//read file to buffer
		FileReader input = new FileReader("reverse_input.txt");
		BufferedReader bufRead = new BufferedReader(input);

		StringBuffer rvsWords = new StringBuffer();//String that holds reversed words
		String line;    // String that holds current file line
		//read text from buffer line by line
		line = bufRead.readLine();
		// Read through file one line at time
		while (line != null){
			//apply string tokenizer
			StringTokenizer tok = new StringTokenizer(line, ".,- \t\n\"", true);
			//follow thought each word
			while (tok.hasMoreElements()) {
				//retrieve next word from string tokenizer
				String word = (String)tok.nextElement();
				
				//put symbols in word in reverse order
				for (int i= word.length()-1; i >=0 ; i--) {
					rvsWords.append(word.charAt(i));
				}
			}
			//read next line from buffer
			line = bufRead.readLine();
			//if not the last line, we'll put the new line separator
			if (line != null){
				rvsWords.append(NEW_LINE_SEPARATOR);
			}
		}
		bufRead.close();
		//write to output file
		File outFile = new File("reverse_output.txt");
		FileWriter writer = new FileWriter(outFile);
		writer.write(rvsWords.toString());
		writer.close();
		
		System.out.println(rvsWords.toString()); //output reverse data to console
		
		
		rvsWords.setLength(0);
	}
}