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Thread: String in java

  1. #1
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    Default String in java

    Greetings


    Consider in a Document if a String " Hello" is Encoded and stored as "XYZAB"

    I want to search the text on document for a word "Hello" and Replace the word with "HelloWorld"

    The Program will encrypt the word "Hello" and Search the file then return the encrypted code as "XYZAB" Found

    Now i have to replace the word "Hello" with "HelloWorld" in encrypted form so that the Letter "XYZABEFGHI" is replace in the place of Hello

    where "World" is encoded as "EFGHI"

    Now the Problem is If there is more number of occurrence of the word "Helloworld" exist in the file... How can i Replace only one particular occurrence What

    can be done to select the particular occurrence.



    Please Do Kindly Help me in sorting out the problem


    i have attached my java program for Encryption along with this mail for your ease of use.


    I Got struct here and cannot proceed further so please please kindly provide me a solution to proceed further...


  2. #2
    Super Moderator Norm's Avatar
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    Default Re: String in java

    Are you assuming how the encryption algorithm works? Will the String "hello" always be encrypted to "xyzab"?
    In a file, The second occurrence could be "asdfre" and the third "ertyu".
    If you don't understand my answer, don't ignore it, ask a question.

  3. #3
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    Default Re: String in java

    What have you tried? What do you have so far?
    Useful links: How to Ask Questions the Smart Way | Use Code Tags | Java Tutorials
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  4. #4
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    Default Re: String in java

    OUTPUT

    Enter the key :
    key
    PlainText : RAGU XYZ RAGU
    CipherText : BEEE VID BEEE



    package javaapplication7;

    import java.io.BufferedWriter;
    import java.io.File;
    import java.io.FileWriter;
    import java.util.Scanner;

    /**
    *
    * @author Ragunath Gunasekaran
    */
    public class JavaApplication7 {

    /**
    * @param args the command line arguments
    */
    public static void main(String[] args) throws Exception

    {

    Scanner in = new Scanner(System.in);
    Scanner file = new Scanner(new File("C:/Users/Ragunath Gunasekaran/Desktop/result.txt"));

    System.out.println("Enter the key : ");


    // TIMER START

    long startTime = System.currentTimeMillis();

    long total = 0;
    for (int i = 0; i < 10000000; i++)
    {
    total += i;
    }



    String key = in.nextLine().toUpperCase();

    String input="";
    while(file.hasNext())
    input+=file.nextLine().toUpperCase();

    System.out.println("PlainText : "+input);

    String cipher="";
    for(int i=0;i<input.length();i++)
    {
    char c = input.charAt(i);
    if(c>='A'&&c<='Z')
    {
    c=(char)(c+(key.charAt(i%key.length())-'A'));
    // if(c<'A')c+=26;
    if(c>'Z')c-=26;
    }
    cipher+=c;
    }

    System.out.println("CipherText : "+cipher);

    FileWriter fstream1 = new FileWriter("C:/Users/Ragunath Gunasekaran/Desktop/final.txt");
    BufferedWriter out = new BufferedWriter(fstream1);
    // cipher = br.readLine();
    out.write(cipher);
    out.close();

    String plaintext1 = "";
    for(int i=0;i<cipher.length();i++)

    {
    char c = cipher.charAt(i);
    if(c>='A'&&c<='Z')
    {
    c=(char)(c-(key.charAt(i%key.length())-'A'));
    if(c<'A')c+=26;
    // if(c>'Z')c-=26;
    }
    plaintext1 +=c;
    }

    // System.out.println("PlainText : "+plaintext1);

    // TIMER Run time & Print
    long stopTime = System.currentTimeMillis();
    long elapsedTime = stopTime - startTime;
    System.out.println("\n Runtime of the Ecryption Program "+elapsedTime);
    //TIME FINISH -Result Finish

    }


    }

  5. #5
    Super Moderator Norm's Avatar
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    Default Re: String in java

    Please edit your post and wrap your code with code tags:
    [code=java]
    YOUR CODE HERE
    [/code]
    to get highlighting and preserve formatting.
    If you don't understand my answer, don't ignore it, ask a question.

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