import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;

public class Scrittura {

	public static void main(String[] args) {

		try {
			FileWriter fw = new FileWriter("dati.txt");
			BufferedWriter bw = new BufferedWriter(fw);

			for (int i = 1; i <= 10; i++) {
				bw.write("3 x " + i + " = " + 3 * i);
				bw.newLine();
			}

			bw.close();
		} catch (IOException e) {
			System.out.println("Errore nel salvataggio dei dati");
		}
	}

}

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

public class Lettura {

	public static void main(String[] args) {

		try {
			FileReader fr = new FileReader("dati.txt");
			BufferedReader br = new BufferedReader(fr);

			for (int i = 1; i <= 10; i++) {
				System.out.println(br.readLine());
			}

			br.close();
		} catch (IOException e) {
			System.out.println("Errore nel salvataggio dei dati");
		}
	}

}