Cipher.java

import java.io.*;
import java.util.*;

public class Cipher{
    
    public ArrayList<String> wordList;

    public static void main(String[] args){
	
	if (args.length == 2){
	    Cipher c = new Cipher(args[0], (Integer.parseInt(args[1])));
	}
	if (args.length == 1){
	    if (args[0].length() > 1){
		System.out.println("No int given");
	    }
	    else{
		System.out.println("No String given");
	    }
	}
	if (args.length == 0){
	    System.out.println ("No parameters given");
	}
    }
    
    public Cipher(String input, int num){
       	input = Decapitalize(input);
	String firstWord = getFirstWord(input);
	String output = "";
	readWords("words.txt");
	System.out.println(Encrypt(input, num));
	System.out.println(Decrypt(input));
    }   

    private String getFirstWord(String input){
	String firstWord = "";
	
	if (input.contains(" ")){
	    for (int i = 0; input.charAt(i) != ' '; i++){
		firstWord += input.charAt(i);
		}
	}.
	else{
	    for (int i = 0; i < input.length(); i ++){
		firstWord += input.charAt(i);
	    }
	}
	return firstWord;
    }

    private void readWords(String filename){	
	int longest = 0;

	wordList = new ArrayList<String>();
	try{
	    Scanner sc = new Scanner(new File(filename));
	    while(sc.hasNext()){
		String s = sc.nextLine();
		wordList.add(s);
		if (s.length() > longest)
		    longest = s.length();
	    }
	}catch (Exception e) {
	    System.out.println(e);
	    System.exit(0);
	}
    }

    private String Decapitalize(String input){
	String output = "";
	for (int i = 0; i < input.length(); i++){
	    if (input.charAt(i) >= 65 && input.charAt(i) <= 90)
		output += (char) (input.charAt(i) + 32);
	    else
		output += input.charAt(i);
	}
	return output;
    }
    
    public String Encrypt(String input, int num){
      	String output = "";
      	
	for(int i = 0; i < input.length(); i++){
	    if (input.charAt(i) + num > 'z' && input.charAt(i) >= 97 && input.charAt(i) <= 122){
		output += ((char) (input.charAt(i) + (num - 26)));
	    }
	    else if(input.charAt(i) + num <= 'z' && input.charAt(i) >= 97 && input.charAt(i) <= 122){
		output += ((char) (input.charAt(i) + num));
	    }
	    else
		output += input.charAt(i);
	}
      	return output;
    } 
    
    public String Decrypt(String input){
	String firstWord = getFirstWord(input);
	System.out.println(firstWord);
	String output = "";

	for (int a = 0; a < 26; a++){
	    if (wordList.contains(Encrypt(firstWord, a))){
		return Encrypt(input, a);
	    }
	}
	return "ERROR";
    }
    

}