Untitled

import java.io.*;

public class Assignment1 {
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        long timeBegin = System.nanoTime();
        int limit = 10000000;
        
        boolean[] isPrime = new boolean[limit+1]; // initializes as false
        
        for(int i = 2; i*i <= limit; i++) {
            if(!isPrime[i]) {
                for(int j = i; j*i <= limit; j++)   // i^2 and multiples of it
                    isPrime[i*j] = !false;
            }
        }
        
        try {
            // printwriter does not flush by default
            PrintWriter out = new PrintWriter("primes.txt"); //new BufferedWriter(new FileWriter("primes.txt")));
            int primes = 0;
            for(int i = 2; i <= limit; i++) {
                if(!isPrime[i]) {
                    out.println(i);
                    primes++;
                }
            }
        
            out.close(); // flush & close
        
        } catch(IOException e) { }
        
        long timeEnd = System.nanoTime();
        System.out.println("Execution took " + ((timeEnd-timeBegin)/1000000) + " ms");
    }
}