encry

import java.util.*;
import java.io.*;
import java.lang.*;
public class Main
{
    static int pass = 0;
    static String ans, backup;
    static Scanner sc = new Scanner(System.in);
    public static String decrypt(String backup)
    {
        int temp, len = backup.length(), i = 0;
        char ans2[] = new char[len];
        char x;
        while (i < len)
        {
            if (pass > 50)
                pass = 0;
            temp = backup.charAt(i);
            temp -= pass;
            x = (char)temp;
            ans2[i] = x;
            i++;
            pass++;
        }
        ans2[len] = '\0';
        return String.valueOf(ans2);
    }

    public static String decryptv2()
    {
        String f;
        System.out.println("Enter the name(with extension) of file you want to open.\n\n\t");
        f = sc.next();
        try
        {
            File file = new File(f);
            BufferedReader br = new BufferedReader(new FileReader(file));
            String str = "", s;
            while ((s = br.readLine()) != null)
                str += s;
            br.close();
            return decrypt(str);
        }
        catch (Exception e)
        {
            System.out.println("File not found");
            return "";
        }
    }

    public static void save(StringBuilder backup)
    {
        String f;
        System.out.println("Enter the name of the file(with extension)\n\n\t");
        f = sc.next();
        try
        {
            FileWriter file = new FileWriter(f);
            file.write(backup.toString());
            System.out.println("The text is succesfully saved in a file named \"" + f + "\"" + (char)24 + "\n\n\t");
            file.close();
            System.in.read();
        }
        catch (Exception e)
        {
            System.out.println("Error occurred while saving the file.");
        }
    }

    public static void save2(StringBuilder backup)
    {
        String f;
        System.out.println("Enter the name of the file(with extension)\n\n\t");
        f = sc.next();
        try
        {
            FileWriter file = new FileWriter(f);
            file.write(backup.toString());
            System.out.println("The text is succesfully saved in a file named \"" + f + "\"" + (char)24 + "\n\n\t");
            file.close();
            System.in.read();
        }
        catch (Exception e)
        {
            System.out.println("Error occurred while saving the file.");
        }
    }

    public static String encrypt(String str)
    {
        int len, i = 0, temp;
        len = str.length();
        char enc[] = new char[len];
        char x;
        while (i < len)
        {
            if (pass > 50)
                pass = 0;
            temp = str.charAt(i);
            temp += pass;
            x = (char)temp;
            enc[i] = x;
            i++;
            pass++;
        }
        enc[len] = '\0';
        pass = 0;
        backup = String.valueOf(enc);
        return String.valueOf(enc);
    }

    public static void encryptv2()
    {
        System.out.println("Enter the Filename(with extension).\n\n\t");
        String str = "", f;
        f = sc.next();
        try
        {
            File file = new File(f);
            BufferedReader br = new BufferedReader(new FileReader(file));
            while (br.ready())
                str += br.readLine();
            br.close();
            backup = encrypt(str);
        }
        catch (Exception e)
        {
            System