import java.util.Scanner;

public class ConsoleValidator {
    private static Scanner s = new Scanner(System.in);

    public static Integer getInteger() {
        Integer result;
        while (true) {
            try {
                String input = s.next();
                result = Integer.parseInt(input);
                return result;
            } catch (Exception e) {
                printErrorMessage();
            }
        }
    }

    public static Double getDouble() {
        Double result;
        while (true) {
            try {
                String input = s.next();
                result = Double.parseDouble(input);
                return result;
            } catch (Exception e) {
                printErrorMessage();
            }
        }
    }

    public static String getString() {
        return s.next();
    }

    private static void printErrorMessage() {
        System.err.println("Niepoprawna wartość");
    }
}