埃氏筛素数法

import java.util.*;public class Sieve {public static void main(String args[]){new Sieve();}Sieve(){System.out.print("input the size of n: ");Scanner s = new Scanner(System.in);int n = s.nextInt();Vector v = new Vector();boolean is_prime[] = new boolean[n+10];//开大一点，小心抛出越界异常Arrays.fill(is_prime,true);int i,j;for(i=2;i<=n;i++){if(is_prime[i]==true){v.add(i);for(j=2*i;j<=n;j+=i){is_prime[j]=false;}}}Iterator it = v.iterator();while(it.hasNext()){System.out.print(it.next()+" ");}System.out.println();}}