import java.io.*;

public class quadrato
{

    static InputStreamReader input= new InputStreamReader (System.in);
    static BufferedReader tastiera= new BufferedReader (input);


    private static double lato=0;

    public static void setlato()
    {
    do
    {
        System.out.print("inserisci il lato del quadrato");
        try
        {
             String latoletto = tastiera.readLine();
             lato = double.valueOf(latoletto).doubleValue();
        }
        catch(Exception e)
        {
        System.out.println("Errore! Inserisci un valore positivo");
        }
        while (lato < 0);

        }
    }

    public static double setper()
    {
        double perim;
        perim = lato * 4;
        return perim;
    }

    public static double setarea()
        {
        double area;
        area = lato * 4;
        return area;
        }
    }