Benchmark

[aux_code language=»javascript» theme=»tomorrow» title=»Benchmark» extra_classes=»»]

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {

    public static void main(String[] args) {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String e = "";
        do {
            try {
                System.out.println("Calcular si un número es primo: fin para salir");
                e = br.readLine();
                if (e.equalsIgnoreCase("fin")) {
                    System.out.println("Me despido.");
                } else {
                    int n = Integer.parseInt(e);
                    if (n <= 1) {
                        System.out.println("El valor ha de ser mayor que 1");
                    } else {
                        long inicio = System.currentTimeMillis();
                        esPrimo(n);
                        long fin = System.currentTimeMillis();
                        System.out.println("Se ha tardado " + (fin - inicio) + " ms.");
                    }
                }
            } catch (IOException | NumberFormatException ex) {
                System.out.println("Sólo valores numéricos, máximo 2147483647 por ser INT");
            }
        } while (!e.equalsIgnoreCase("fin"));
    }

    private static void esPrimo(int e) {
        System.out.println("2");
        for (int y = 2; y <= e; y++) {
            if (y % 2 != 0) {
                int x = y - 1;
                do {
                    if (y % x == 0) {
                        x = 0;
                    } else {
                        x--;
                        if (x <= 1) {
                            x = 1;
                        }
                    }
                } while (x > 1);
                if (x == 1) {
                    System.out.println(y);
                }
            }
        }
    }
}

[/aux_code]