Thread: anyone can help me to solve this?

Only "bila" is supposed to go in the array

Can you describer how the program is supposed to work? List the steps the code should do to solve the problem.
What is the name of the array you are working with? How are the values put in the array?

SUBSTITUTION ENCRYPTION
This type of encryption works by substituting the first few characters for the key typed in by user. For example, if the key is WREAKHAVOC, the substitution table would look like:
KEY: WREAKHAVOC
A B C D E F G H I J
W R E A K H V O C A
K L M N O P Q R S T
B D F G I J L M N P
U V W X Y Z
Q S T U X Z

Notes:
• In the key, WREAKHAVOC, the letter A appears twice, but only one substitution will be used, in this case D
• Encryption:
o Plain Text: ATTACK AT DAWN
o Cipher Text: WPPWEK WP AWTG
• Decryption:
o Cipher Text: HDKK WP IGEK
o Plain Text: FLEE AT ONCE

These look like two different problems. Which one are you working on?

Is this a question about creating an algorithm
or about how to code an algorithm in java?

Can you be more specific? Post #1 is about removing duplicates. Post#2 is about encoding.

Are you looking for algorithms to solve these problems
or do you have the algorithm and need help writing a java program for the algorithm?

If you have code you are having problems with, post the code (please wrap it in code tags) and ask any questions.
Wrap your code with[code=java]<YOUR CODE HERE>[/code] to get highlighting

post #4 is not an algorithm for solving the problem. It is a partial statement of the problem with an example.
An algorithm is a list of steps that will solve the problem. You have not provided that yet.

In post#4 there is a table with some lines of letters:

A	B	C	D	E	F	G	H	I	J
W	R	E	A	K	H	V	O	C	A   <<< From key
K	L	M	N	O	P	Q	R	S	T
B	D	F	G	I	J	L	M	N	P   <<< ???
U	V	W	X	Y	Z	
Q	S	T	U	X	Z	                            <<<????

The second line looks like it was created from the key. What are the rules for creating this line from the key?
What are the rules for creating the fourth and sixth lines?

Have you created a design in pseudo code for the problem? A list of the steps the program needs to do to solve it.



Also posted at http://www.java-forums.org/new-java/...-help-pls.html

this is the code my member send it to me...do u guys have any idea how can we make it more Object oriented,the lecturer will not like if we only used one class..and how to encrypt things with space. For example "the world". Right now the program can only encrypt 1 word.

package substitutionencryption;
 
import java.util.Scanner;
 
public class SubstitutionDemo
{
public static void main(String[] args)
{
 
Scanner bb = new Scanner(System.in);
System.out.println("Please enter the key.");
String key = bb.nextLine();
System.out.println("If you would like to encrypt, type [E]."
+ " If you would like to decrypt, type [D]");
String answer = bb.nextLine();
char choice = answer.charAt(0);
 
if (choice == 'e' || choice == 'E'){
System.out.println("Please enter the plain text.");
String plaintext = bb.nextLine();
encryption(key, plaintext);
}
else
System.out.println("Please enter the cipher text.");
String ciphertext = bb.nextLine();
decryption(key, ciphertext);
}
 
public static void encryption(String ps, String pl){
 
char [] letters = {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h',
'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q',
'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'};
String password = ps;
String plaintext = pl;
password = password + "abcdefghijklmnopqrstuvwxyz";
int kk = password.length();
char [] userEntered = password.toCharArray();
char [] userFixed = new char [kk];
char [] plainx = plaintext.toCharArray();
 
int l = 0;
 
for(int i = 0; i < userEntered.length; i++){
char x = userEntered[i];
if (Character.isLetter(x)) {
boolean Insert = true;
for(int j = 0; j < userEntered.length; j++){
if (userFixed[j] == x)
Insert=false;
}
if (Insert) {
userFixed[l] = x;
l++;
}
}
}
 
for(int i = 0; i < plainx.length; i++){
for(int x = 0; x < letters.length; x++){
if (plainx[i] == letters[x])
System.out.print(userFixed[x]);
}
}
}
 
public static void decryption(String la, String pn) {
char [] letters = {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h',
'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q',
'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'};
String password = la;
String cipher = pn;
password = password + "abcdefghijklmnopqrstuvwxyz";
int kk = password.length();
char [] userEntered = password.toCharArray();
char [] userFixed = new char [kk];
char [] cipherx = cipher.toCharArray();
 
int l = 0;
for(int i = 0; i < userEntered.length; i++){
char x = userEntered[i];
if (Character.isLetter(x)) {
boolean Insert = true;
for(int j = 0; j < userEntered.length; j++){
if (userFixed[j] == x)
Insert=false;
}
if (Insert) {
userFixed[l] = x;
l++;
}
}
}
 
for(int i = 0; i < cipherx.length; i++){
for(int x = 0; x < userFixed.length; x++){
if (cipherx[i] == userFixed[x])
System.out.print(letters[x]);
}
}
}
}

Please edit the code and add indentations to show the nesting level. This unformatted, (all statements in starting in column one) is hard to read and understand.