Project #5 Caesar Cipher

Code

    Name: Iaroslav Titov
    Period: 7
    Project Name: CaesarCipher
    File Name: CaesarCipher.java
    Date: 3/16/2015
    
import java.util.Scanner;
import java.io.File;
import java.io.PrintWriter;
import java.util.InputMismatchException;
import java.io.IOException;

public class CaesarCipher {

    public static char shiftLetter(char c, int n) {

        int u = c;

        if(!Character.isLetter(c))
            return c;

        u = u + n;

        if(Character.isUpperCase(c) && u > 'Z' || Character.isLowerCase(c) && u > 'z') {
            u -= 26;
        }

        if(Character.isUpperCase(c) && u < 'A' || Character.isLowerCase(c) && u < 'a') {
            u += 26;
        }

        return (char)u;
    }

    public static void main(String[] args)
    {
        System.out.println("\n Welcome to the CipherCreator by TIS!!!\n");


        boolean mode = getMode();
        File input = getFile(true);

        Scanner fileIn = new Scanner(System.in);
        try
        {
            fileIn = new Scanner(input);
        }
        catch(IOException e){System.out.println("FILE NOT FOUND");}

        File output = getFile(false);
        int shift = getShift() * (mode? 1:-1);

        String plainText = "";
        String cipher = "";
        while (fileIn.hasNext())
        {
            plainText += fileIn.nextLine();
            plainText +="\n";
        }
        for(int i = 0; i < plainText.length(); i++)
        {
            cipher += shiftLetter(plainText.charAt(i), shift);
        }
        fileIn.close();

        outputToFile(cipher, output.getName());

        System.out.print("\n Output successful!\n >");
    }

        public static void outputToFile(String cipher, String name)
        {
            PrintWriter fileOut = null;
            while (fileOut==null)
            {
                try {
                    fileOut = new PrintWriter(name);
                } catch(Exception e){System.out.println("OUTPUT FILE NOT FOUND");}
            }

            fileOut.print(cipher);

            fileOut.close();
        }

    public static boolean getMode()
    {
        Scanner in = new Scanner(System.in);
        String read = "";
        while (!(read.equals("encrypt") || read.equals("decrypt")) )
        {
            System.out.print(" Do you want to encrypt or decrypt?\n >");
            try
            {
                read = in.nextLine();
            }
            catch (InputMismatchException e)
            {
                System.out.print("\n"+read+" is not an accepted command.\n");
                read = "";
            }
        }

        if (read.equals("encrypt")) return true;
        else return false;
    }

    public static int getShift()
    {
        Scanner input = new Scanner(System.in);
        int shift = 0;
        while (shift==0)
        {
            System.out.print("\n What is the shift?\n > ");
            try
            {
                shift = input.nextInt();
            }
            catch (InputMismatchException e){shift = 0;};
        }

        return shift;
    }

    public static File getFile(boolean input)
    {
            Scanner in = new Scanner(System.in);
            File file = null;
            boolean good = false;
            while (!good)
            {
                try
                {
                    if (input) System.out.print("\n Put in source file name\n >");
                    else System.out.print("\n Put in output file name\n >");
                    file = new File(in.nextLine());
                    if(file.exists() && !file.isDirectory()) good = true;
                    else
                    {
                        good = false;
                        System.out.print("\n File does not exist!!!\n");
                    }
                }
                catch (Exception e)
                {
                    file = null;
                }
            }
            return file;
    }
}




    

Picture of the output