Προγραμματισμός Java

import java.util.Scanner;

int answer = 0;
        do{
            System.out.print(" Bale eisodo: ");
            Scanner in = new Scanner(System.in);
            answer = in.nextInt();
        }while(answer != 1 && answer != 2);

public class epi {
	
	public static void main(String args[])
	{
		int count = 1;
		int poso = 1;
		int total;
		
		while (count > 0)
		{	
			total = poso * 2;
			System.out.println(total);
			poso = total * 2;	//ή poso = poso * 2
			++count;
		}
	}
}

package secret;
import java.util.*;

public class secret {
	
	public static void main(String args[])
	{
		Scanner input = new Scanner(System.in);
		int number;
		
		System.out.println("Enter the number: ");
		number = input.nextInt();
		
		// Παίρνω μεμονωμένα τα ψηφία απο τον εισαγόμενο αριθμό
		int ena = (number / 1000) % 10;
		int duo = (number / 100) % 10;
		int tria = (number / 10) % 10;
		int tessera = number % 10;
		
		System.out.println(ena + " " + duo + " " + tria + " " + tessera);
		
		// Κρυπτογράφηση και καλά!!!
		int newEna = (ena + 7) % 10;
		int newDuo = (duo + 7) % 10;
		int newTria = (tria + 7) % 10;
		int newTessera = (tessera + 7) % 10;
		
		System.out.println(newEna + " " + newDuo + " " + newTria + " " + newTessera);
		// Και αλλάζω και τη σειρά
		System.out.println(newTria + " " + newTessera + " " + newEna + " " + newDuo );
		
		// Μετατρέπω σε String
		String i = "" + newTria+""+newTessera+""+newEna+""+newDuo;
		System.out.println(i);
		
		// Μετατρέπω από String σε Int
		int mi = Integer.valueOf(i).intValue();
		System.out.println(mi);
		
		/* Πως κάνω με κωδικοποίηση πάλι να επιστρέψει τον αρχικό 
αριθμό?
		 * Δηλαδή κυρίως πως να επαναφέρω το κάθε ψηφίο μετά τη 
μετατροπή του με το '(ena + 7) % 10'
		 */
	}
	
	
}

package secret;
import java.util.*;

public class secret {
	
	
		Scanner input = new Scanner(System.in);
		private int number;
		
		public secret(int theNumber)
		{
			theNumber = number;
		}
		
		public void setNumber(int theNumber)
		{				
		        theNumber = number;
		        System.out.println("Enter the number: ");
		        number = input.nextInt();
		
		        // Παίρνω μεμονωμένα τα ψηφία απο τον εισαγόμενο αριθμό
		        int ena = (number / 1000) % 10;
		        int duo = (number / 100) % 10;
		        int tria = (number / 10) % 10;
		        int tessera = number % 10;
				
		        // Κρυπτογράφηση και καλά!!!
		        int newEna = (ena + 7) % 10;
		        int newDuo = (duo + 7) % 10;
		        int newTria = (tria + 7) % 10;
		        int newTessera = (tessera + 7) % 10;
		
		        String teliko = newTria+""+newTessera+""+newEna+""+newDuo; // Μετατρέπω σε String
		        number = Integer.valueOf(teliko).intValue();
		
		}
		public int getNumber()
		{
			return number;
		}
		
		public void displayMessage()
		{
			
			System.out.println( getNumber() );
				
		}
				
	
}

package secret;

public class secreTest {
	
	public static void main(String[] args)
	{
		secret mySecret = new secret();
				
		mySecret.setNumber();
		mySecret.getNumber();
		
		// Εδώ και κάτω θα έκανα τη μετατροπή του "κωδικοποιημένου" αριθμού στον αρχικό
		int a = (newEna + 3) % 10;
		int b = (newDuo + 3) % 10;
		int c = (newTria + 3) % 10;
		int d = (newTessera + 3) % 10;
			
		String teliko = ""+a+""+b+""+c+""+d; // Μετατρέπω σε String
		int telos = Integer.valueOf(teliko).intValue(); // Μετατρέπω σε Int
		System.out.println(telos);		
		
		
		
	}
}

package quizAdvanced;
import java.util.*;

public class quizAdvanced {

	public static void main(String[] args) {
		
		Scanner input = new Scanner(System.in);
		String[] a = new String[5];
		String[] b = new String[5];
		String[] c = new String[5];
		
		int count = 0;
		String answer;
		int correct = 0;
		int wrong = 0;
		
		a[0] = "G. Bush Jr.";
		a[1] = "Obama";
		a[2] = "Lincoln";
		a[3] = "Washington";
		a[4] = "Papandreou";
		
		b[0] = "Apple";
		b[1] = "Motorola";
		b[2] = "Lenovo";
		b[3] = "Sony";
		b[4] = "Google";
		
		c[0] = "Doha";
		c[1] = "Boha";
		c[2] = "Al Khtor";
		c[3] = "Loha";
		c[4] = "Dammam";
		
		while (count < 3) {
			
			switch (count) {
			
			case 0:
				System.out.printf("%s\n \na) %s\nb) %s\nc) %s\nd) %s\ne) %s\n %s\n", "Who is the president of U.S.A?", 
						a[0],a[1],a[2],a[3],a[4], "Enter the answer: ");
				answer = input.nextLine();
				
				if (answer == "b" || answer == "Obama")
					++correct;
				else
					++wrong;
				break;
				
			case 1:
				System.out.printf("%s\n \na) %s\nb) %s\nc) %s\nd) %s\ne) %s\n %s\n", "Which company of the following created Android software?", 
						b[0],b[1],b[2],b[3],b[4], "Enter the answer: ");
				answer = input.nextLine();
				
				if (answer == "e" || answer == "Google")
					++correct;
				else
					++wrong;
				break;
				
			default:
				System.out.printf("%s\n \na) %s\nb) %s\nc) %s\nd) %s\ne) %s\n %s\n", "What's the capital of Qatar?", 
						c[0],c[1],c[2],c[3],c[4], "Enter the answer: ");
				answer = input.nextLine();
				
				if (answer == "a" || answer == "Doha")
					++correct;
				else
					++wrong;
				break;
			}
			
			++count;
		}
		
		System.out.println("Results: ");
		if (correct == 3)
			System.out.println("Congrats! 3 out of 3.");
		else if (correct == 2)
			System.out.println("Good,but you could be better.");
		else
			System.out.println("You failed!");
		
		System.out.println(correct +" - " + wrong);
	}
}