How to invert a word String

**Truffy** · July 21st, 2009, 09:57 PM

import java.io.*;
 
/**
 * JavaProgrammingForums.com
 */
public class WordInverter {
 
    private static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
 
    public static void main(String[] args) throws IOException
    {
        String strInv = null, word;
        System.out.print("Enter a word : ");
        word = br.readLine();
        strInv = invert(word);
 
        System.out.println(strInv);
    }
 
    public static String invert(String s) {
        String temp = "";
        for (int i = s.length() - 1; i >= 0; i--)
            temp += s.charAt(i);
        return temp;
    }
}

Cheers,

Truffy

**Json** · July 22nd, 2009, 02:21 AM

Or you can use the built in feature of the java.lang.StringBuilder

        final StringBuilder stringBuilder = new StringBuilder("MyString");
        System.out.println(stringBuilder.reverse());

// Json

**JavaPF** · July 22nd, 2009, 09:38 AM

Hello Truffy,

Thank you very much for that submission. I edited it slightly just to clean it up.

Keep up the good work

**Truffy** · July 23rd, 2009, 01:01 AM

Originally Posted by JavaPF

Hello Truffy,

Thank you very much for that submission. I edited it slightly just to clean it up.

Keep up the good work

Thanks JavaPF and Json.

Cheers,

Truffy

**niraj** · August 2nd, 2009, 02:35 PM

take two pointer and start swapping .

**Freaky Chris** · August 2nd, 2009, 03:11 PM

Originally Posted by niraj

take two pointer and start swapping .

Would you like to elaborate on this point please. Since Java doesn't use pointers, this is not possible. If this were a C or C++ forum then it would be acceptable, so please explain what you mean.

Thanks,
Chris

**Truffy** · August 2nd, 2009, 07:31 PM

Originally Posted by Freaky Chris

Would you like to elaborate on this point please. Since Java doesn't use pointers, this is not possible. If this were a C or C++ forum then it would be acceptable, so please explain what you mean.

Thanks,
Chris

Yup, I agree with Cris. I think C and C++ uses pointers. Java doesn't uses pointers.

**helloworld922** · August 18th, 2009, 08:37 PM

well, technically all object variables are pointers...

**JSoFt** · August 20th, 2009, 12:09 AM

hi i think truffy's simple program is far more usefull than the preDefined class
String builder.reverse in java.

truffy's program can accept data(Strings of characters) and it will reverse it
unlike String builder it only accepts arguments
i supposed it was made with a VOID type of return

**Json** · August 20th, 2009, 08:40 AM

I'm not entirely sure what you are on about here, but the StringBuilder will accept strings, in fact whenever you write code in Java like this.

final String myString = "some cool string here " + "with some more data here"

That will in the compiled Java byte code be something like this.

    final StringBuilder stringBuilder = new StringBuilder();
    stringBuilder.append("some cool string here ");
    stringBuilder.append("with some more data here");

A wee bit of reading for you is available at StringBuilder (Java Platform SE 6)

If you would like it as a method that takes a string and returns a string, this is what you could do.

    public String reverse(final String input) {
        return new StringBuilder(input).reverse().toString();
    }

// Json

**Freaky Chris** · August 22nd, 2009, 01:02 AM

Originally Posted by helloworld922

well, technically all object variables are pointers...

they are references, and we cannot deal with the pointers / references ourself. Java does all of that and so we have no input on it, unlike C where you have to do it all yourself.

**helloworld922** · August 22nd, 2009, 07:24 PM

they behave more like C pointers than C references cause they're not static (thank goodness!). But yes, this makes absolutely no sense in Java but does in C (well, at least it compiles).

SomeObject a = new SomeObject();
a++;

SomeObject *a = new SomeObject();
a++;

**chronoz13** · August 26th, 2009, 02:51 AM

pointers pointers.. please elaborate to me what those pointer do..

please give me some statements on what a pointer means.. in C and the equivalent of pointers in java

**Freaky Chris** · August 27th, 2009, 08:31 AM

Warning: Pointers are known to confuse the hell out of a lot of people!

Contributor's Corner

**psrkiran** · October 2nd, 2009, 10:05 PM

Use function in String class

public String reverse()

**helloworld922** · October 3rd, 2009, 01:07 AM

chronoz, you may not want to know what pointers are

They are not available in Java, and still confuse me on how and when to use them (granted, it's been quite a while since i've used C/C++)

**chronoz13** · October 3rd, 2009, 02:44 AM

tnx helloworld sori for being hardheaded i just got curious about the post that says 'use pointers' bla bla
although some of you says that THERE are no pointers in java and it only exist in C languages i still
researched a liitle bit about it.. and what ive learned is that pointer is another data type..for some memory alocation for a declared variable... whahahahah anyway tnx... !!

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