How to solve Java BufferString problem? I mean clearing buffer

Question

I have little problem with my code, I split in Java String to table, then for I pick selected char and replace it with StringBuffer method. The problem is when I use sout method at the end with extracted toString(), my ciphered value is automatically displayed with raw value that at the beginning I wanted to cipher. I tried a lot with clearing BufferedStream but can not disattach it. See also picture below code enter image description here

public class third {
    public static void main(String[] args) {
        String letter = "drukarka";
        String[] tab1 = letter.split("");
        String result = "Result of cypher: ";
        StringBuffer cypher = new StringBuffer("drukarka");


        for (int i = 0; i < tab1.length; i++) {
            String word = tab1[i];
            int k = tab1.length;
            k--;
            if (word.equals("d")) {
                cypher.replace(Integer.valueOf(tab1.length-k-1), Integer.valueOf(tab1.length-k-1), "#");
            } else if (word.equals("r")) {
                cypher.replace(Integer.valueOf(tab1.length-k-1), Integer.valueOf(tab1.length-k-1), "!");
            } else if (word.equals("u")) {
                cypher.replace(Integer.valueOf(tab1.length-k-1), Integer.valueOf(tab1.length-k-1), "$");
            } else if (word.equals("k")) {
                cypher.replace(Integer.valueOf(tab1.length-k-1), Integer.valueOf(tab1.length-k-1), "&");
            } else if (word.equals("a")) {
                cypher.replace(Integer.valueOf(tab1.length-k-1), Integer.valueOf(tab1.length-k-1), ";");
            }
        }
        String[] cypher2 = cypher.toString().split("");
        StringBuffer cypher3 = new StringBuffer("");
        for (int i = 0; i < cypher2.length; i++) {
            cypher3.append(cypher2[i]);
        }
        String cyphered = String.valueOf(cypher3);
        cypher.setLength(0);
        cypher3.setLength(0 );
        thirdd construction = new thirdd();
        construction.constructor(letter, result, cyphered);
        System.out.println(construction.toString());
    }

}

Answer 1

Your code is rather weird. You want to replace the letters in cypher, but you aren't replacing them. Instead it looks like you are always inserting the replacements at the very end of the string.

I think you want something like this (not tested)

public class third {
    public static void main(String[] args) {
        String input = "drukarka";
        StringBuffer cypher = new StringBuffer();

        // Get each character in the input string
        for (int i = 0; i < input.length; i++) {
            // Append a new cypher character depending on the input character
            switch (input.charAt(i))
                case 'd':
                    cypher.append('#');
                    break;
                case 'r':
                    cypher.append('!');
                    break;
                case 'u':
                    cypher.append('$');
                    break;
                case 'k':
                    cypher.append('&');
                    break;
                case 'a':
                    cypher.append(';');
                    break;
            }
        }

        String result = cypher.toString();

        // Rest of the code skipped because I'm not sure what you are trying to do.
    }

}

Or an even simpler version:

public class third {

    public static void main(String[] args) {
        String input = "drukarka";
        StringBuffer cypher = new StringBuffer();
        HashMap<Character, Character> charMap = new HashMap<>();

        // Create a map that maps an input character to its cypher version
        charMap.add('d', '#');
        charMap.add('r', '!');
        charMap.add('u', '$');
        charMap.add('k', '&');
        charMap.add('a', ';');

        for (int i = 0; i < input.length; i++) {
            // look up each character in the charMap and
            // append it to our output cypher
            cypher.append( charMap.get(input.charAt(i)) );
        }

        String result = cypher.toString();
    }

}