Thread: How To Compare String input to char Array....

Good evening everybody. I hope you all are well. SoS on my end.

Anyway, at the moment I'm sort of stuck on a "how will I do that" hump and I'm hoping someone won't mind pushing me over. What I'm trying to do is compare String input to a char array. Let me make it a little more plain, I'm working on a cipher assignment, and my line of thought is this: I will get String input from the user, COMPARE the characters in the string input to an alphabet array, which will then be compared to the cipher array so that the cipher's counterpart can be chosen over the alphabet's. Does that make sense? If so, and this isn't a horrible approach to the problem, can anyone suggest a way that I might compare the random input keyed in by the user to that alphabet array?

Anyone?........Anyone?........Anyone?



Thanks all the same.

The thread title and description don't correspond, so I'm not sure what the question is. Can you show an example of what you're trying to do, step by step? Input word, comparison to alphabet array, compared to cipher array, resulting output word. It sounds like a simple substitution cipher, but I'm not completely sure.

Well, that's pretty much what it is, an Atbash cipher. I can compare the two arrays, one being the standard alphabet, and the other being the cipher using the following code:

public class ArrayTest
{
   public static void main(String[] args)
   {
      char [] alphabet;
      alphabet = new char[26];
      alphabet[0] = 'A';
      alphabet[1] = 'B';
      alphabet[2] = 'C';
      alphabet[3] = 'D';
      alphabet[4] = 'E';
      alphabet[5] = 'F';
      alphabet[6] = 'G';
      alphabet[7] = 'H';
      alphabet[8] = 'I';
      alphabet[9] = 'J';
      alphabet[10] = 'K';
      alphabet[11] = 'L';
      alphabet[12] = 'M';
      alphabet[13] = 'N';
      alphabet[14] = 'O';
      alphabet[15] = 'P';
      alphabet[16] = 'Q';
      alphabet[17] = 'R';
      alphabet[18] = 'S';
      alphabet[19] = 'T';
      alphabet[20] = 'U';
      alphabet[21] = 'V';
      alphabet[22] = 'W';
      alphabet[23] = 'X';
      alphabet[24] = 'Y';
      alphabet[25] = 'Z';  
      System.out.println(alphabet);
 
      char [] cipher;
      cipher = new char[26];
      cipher[0] = 'Z';
      cipher[1] = 'Y';
      cipher[2] = 'X';
      cipher[3] = 'W';
      cipher[4] = 'V';
      cipher[5] = 'U';
      cipher[6] = 'T';
      cipher[7] = 'S';
      cipher[8] = 'R';
      cipher[9] = 'Q';
      cipher[10] = 'P';
      cipher[11] = 'O';
      cipher[12] = 'N';
      cipher[13] = 'M';
      cipher[14] = 'L';
      cipher[15] = 'K';
      cipher[16] = 'J';
      cipher[17] = 'I';
      cipher[18] = 'H';
      cipher[19] = 'G';
      cipher[20] = 'F';
      cipher[21] = 'E';
      cipher[22] = 'D';
      cipher[23] = 'C';
      cipher[24] = 'B';
      cipher[25] = 'A';
      System.out.println(cipher);
 
      for (int i = 0; i < alphabet.length; i++) //Here I compare the arrays and convert cipher to alphabet.
      {
         cipher[i] = alphabet[i];
 
      }
        System.out.println(cipher); 
 
   }
}

That works fine, but my question is this: how will I be able to compare the actual input that the user keys in, to the alphabet array?

Something like the following?

while(input.next()==alphabet[i])

I'm just not sure.
Thanks for replying.

Looking those up now. Thanks Norm.

You might be interested to know that

alphabet[1] = alphabet[0] + 1;

You didn't need to type all of that out. Similarly could have been done for your cipher[] array, but I would have generated that randomly.

GregBrannon, yes, thank you. I definitely needed to know that. I knew there had to be a more efficient way to build those arrays. I knew enough to know that I should be embarrassed by having keyed all that in. Alas...I have much to learn. Thanks again.

Actually, to be honest, although I'm sure this works else you wouldn't have said so, I don't quite understand it...

alphabet[1] = alphabet[0] + 1;

Or perhaps I don't understand what this statement can take the place of. I'm assuming that you mean the complete alphabet array that I typed out. If that is the case, unless the alphabet is just something assumed by JAVA, how will it know what the next character should be and so on?

Ahhh, ok. I see. And I see how that can be useful.

Let me ask you something else Norm, if you don't mind: I have what I call my general Neandarcode written for this program and would like to have it critiqued. Where would you advise I post it, before I post it in the wrong thread. You see, this program is to use command-line arguments and written in Eclipse, neither of which I am very familiar with and therefore have no idea how I can test it.

I apologize if I was too terse. My point was that you could do something like:

char[] alphabet = new char[26];
alphabet[0] = 'A';
 
// fill in the rest of the alphabet array
for ( int i = 1 ; i < alphabet.length ; i++ )
{
    alphabet[i] = (char)( alphabet[i - 1] + 1 );
}

No, no. No need to apologize. You were quite clear. I just don't have my best "listening ears" on right now.

To the moderator on-duty, or anyone who knows:
I have what I call my general Neandarcode written for this program and would like to have it critiqued. Where would you advise I post it, before I post it in the wrong thread. You see, this program is to use command-line arguments and written in Eclipse, neither of which I am very familiar with and therefore have no idea how I can test it.

I'm not sure what you want. Do you want to know:

1. How to add command-line inputs when running in Eclipse?
2. How to run a program written in Eclipse from a command line?
3. Someone to smell your code and tell you what smells?

When you figure out the question, post an appropriate thread in an appropriate location. If none seem right, use "What's wrong with my code?" where most everything ends up anyway.