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Thread: Using args level arguments

  1. #1
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    Default Using args level arguments

    What I need to do is use the args command to choose which method to go to. For instance, I have methods encrypt, decrypt, and crack. The user will open their command and prompt this:
    C:\Users\Name\File>java myCodeName methodchoice inputfile outputfile key
    Where myCodeName is the name of my program, methodchoice is either encrypt, decrypt or crack; inputfile is whatever file they want to input, outputfile whatever they want to output and key is the key to the encryption (not necessary for using the crack method)

    I'm just unsure how to pull each string from the args in order so that I can do repeated if loops or something like that. Here is my code:
    public class Encrypt {
    	public static void main(String[] args) {
    		String command = args;
    		if (command.equalsIgnoreCase(encrypt) {
    			}
     
    	}
    	public static void encrypt(char[] array, int key) {
    		try {
    			FileWriter filewriter = new FileWriter(new File(""));
    			for (int i = 0; i < array.length; i++) {
    				char space = ' ';
    				if (array[i] != space) {
    					int charAsNum = (int) array[i] -97;
    					int decode = charAsNum + key;
    					if (decode > 25) {
    						decode = decode % key;
    					}
    					decode = decode + 97;
    					char numAsChar = (char)decode;
    					filewriter.write(numAsChar);
    				}
    				else {
    					char numAsChar = ' ';
    					filewriter.write(numAsChar);
    				}
    			}
    			filewriter.close();
     
    		}
    		catch (java.io.IOException ex) {
    			System.out.println("File not created");
    			System.exit(-1);  
    		}
     
    	}
    	public static void decrypt(char[] array, int key) {
    		try {
    			FileWriter filewriter = new FileWriter(new File("decrypt.txt"));
    			for (int i = 0; i < array.length; i++) {
    				char space = ' ';
    				if (array[i] != space) {
    					int charAsNum = (int) array[i] -97;
    					int decode = charAsNum - key;
    					if (decode < 0) {
    						decode = decode + 25;
    					}
    					if (decode > 25) {
    						decode = decode % key;
    					}
    					decode = decode + 97;
    					char numAsChar = (char)decode;
    					filewriter.write(numAsChar);
    				}
    				else {
    					char numAsChar = ' ';
    					filewriter.write(numAsChar);
    				}
    			}
    			filewriter.close();
     
    		}
    		catch (java.io.IOException ex) {
    			System.out.println("File not created");
    			System.exit(-1);  
    		}
    	}
    	public static void crack(char[] array) {
    				int[] code = new int[array.length];
    				for (int i = 0; i < array.length; i++) {
    					char space = ' ';
    					if (array[i] != space) {
    						code[i] = (int)array[i] - 97;
    					}
    					if (array[i] == space) {
    						code[i] = 27;
    					}
    				}
    				int[] count = new int[28];
    				for (int i = 0; i <code.length; i++) {
    					count[code[i]]++;
    				}
    				int max = count[0];
    				int indexOfMax = 0;
    				for (int i = 1; i < count.length; i++) {
    					if (count[i] > max && count[i] < count[27]) {
    						max = count[i];
    						indexOfMax = i;
    					}
    				}
    				indexOfMax = indexOfMax + 97;
    				int key = 101 - indexOfMax;
    				key = key * -1;
    				decrypt(array ,key);
    		}
    	}
    }

    I am also unsure on how to turn the filewriter into the name they want, but I'm fairly certain that can be done by adding a file x to the method's parameters itself.
    Last edited by taze; November 7th, 2013 at 06:28 PM. Reason: new question.


  2. #2
    Super Moderator Norm's Avatar
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    Default Re: Using args level arguments

    how to pull each string from the args
    java myCodeName methodchoice inputfile outputfile key
     args[] indexes:      0          1         2        3
    If you don't understand my answer, don't ignore it, ask a question.

  3. #3
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    Default Re: Using args level arguments

    So I have it all done, now I just have one really bizarre issue.
    You know Archie Comic's Svenson? For some reason that is the accent of my decryption software.
    The output that is supposed to come out is:
    \he more you eat the better you feel beans beans for every meal
    the key to success is to be open to opportunity
    Instead, this is what comes out:
    the more vou eat the better vou feel beans beans for everv mealthe kev to success is to be open to opportunitv
    a) I can't get the lines to separate so it is the format above and b) all my 'y's are being turned into 'v's.

    My current code:
    import java.util.*;
    import java.io.*;
    public class Encri {
    	public static void main(String[] args) {
    		try { 
    			String command = args[0];
    			String input = args[1];
    			String output = args[2];
    			File file = new File(input);
    			Scanner scanner = new Scanner(file);
    			String theString = scanner.nextLine();
    			while (scanner.hasNextLine()) {
    			       theString = theString + scanner.nextLine();
    			}
    			char[] charArray = theString.toCharArray();
    			if (command.equalsIgnoreCase("encrypt")) {
    					String keyString = args[3];
    										Scanner scanned = new Scanner(keyString);
     
    					int key = scanned.nextInt();
    					encrypt(charArray, key, output);
    			}
    			if (command.equalsIgnoreCase("decrypt")) {
    				String keyString = args[3];
    								Scanner scanned = new Scanner(keyString);
    				int key = scanned.nextInt();
    				decrypt(charArray, key, output);
     
     
    			}
    			if (command.equalsIgnoreCase("crack")) {
    				crack(charArray,output);
    			}
    		}
    		catch (java.io.FileNotFoundException ex) {  
    		System.out.println("File not found.");
    		}
     
    	}
    	public static void encrypt(char[] array, int key, String output) {
    		try {
    			FileWriter filewriter = new FileWriter(new File(output));
    			for (int i = 0; i < array.length; i++) {
    				char space = ' ';
    				if (array[i] != space) {
    					int charAsNum = (int) array[i] -97;
    					int decode = charAsNum + key;
    					if (decode > 25) {
    						decode = decode % key;
    					}
    					decode = decode + 97;
    					char numAsChar = (char)decode;
    					filewriter.write(numAsChar);
    				}
    				else {
    					char numAsChar = ' ';
    					filewriter.write(numAsChar);
    				}
    			}
    			filewriter.close();
     
    		}
    		catch (java.io.IOException ex) {
    			System.out.println("File not created");
    			System.exit(-1);  
    		}
     
    	}
    	public static void decrypt(char[] array, int key, String output) {
    		try {
    			FileWriter filewriter = new FileWriter(new File(output));
    			for (int i = 0; i < array.length; i++) {
    				char space = ' ';
    				if (array[i] != space) {
    					int charAsNum = (int) array[i] -97;
    					int decode = charAsNum - key;
    					if (decode < 0) {
    						decode = decode + 25;
    					}
    					if (decode > 25) {
    						decode = decode % key;
    					}
    					decode = decode + 97;
    					char numAsChar = (char)decode;
    					filewriter.write(numAsChar);
    				}
    				else {
    					char numAsChar = ' ';
    					filewriter.write(numAsChar);
    				}
    			}
    			filewriter.close();
     
    		}
    		catch (java.io.IOException ex) {
    			System.out.println("File not created");
    			System.exit(-1);  
    		}
    	}
    	public static void crack(char[] array, String output) {
    		int[] code = new int[array.length];
    		for (int i = 0; i < array.length; i++) {
    			char space = ' ';
    			if (array[i] != space) {
    				code[i] = (int)array[i] - 97;
    			}
    			if (array[i] == space) {
    				code[i] = 27;
    			}
    		}
    		int[] count = new int[28];
    		for (int i = 0; i <code.length; i++) {
    			count[code[i]]++;
    		}
    		int max = count[0];
    		int indexOfMax = 0;
    		for (int i = 1; i < count.length; i++) {
    			if (count[i] > max && count[i] < count[27]) {
    				max = count[i];
    				indexOfMax = i;
    			}
    		}	
    		indexOfMax = indexOfMax + 97;
    		int key = 101 - indexOfMax;
    		key = key * -1;
    		decrypt(array,key,output);
    	}
    }

  4. #4
    Super Moderator Norm's Avatar
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    Default Re: Using args level arguments

    the lines to separate
    What happened to the newline characters that were in the input file? If they are not preserved, the lines will be run together.


    all my 'y's are being turned into 'v's.
    Have you tested the code with all 26 letters: abc...xyz to see if any others are a problem?
    If you don't understand my answer, don't ignore it, ask a question.

  5. #5
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    Default Re: Using args level arguments

    I fixed the second (the y's being v's) with a minor tweak in the decrypt method, I have no idea how, in the above code, I can save the newline characters so the output will print out correctly.

  6. #6
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    Default Re: Using args level arguments

    What if the code encrypts all the characters in the input file including the newline characters?
    If you don't understand my answer, don't ignore it, ask a question.

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