>>698
public class Prime{public static void main(String[]args){int N=30;
int i,j;int[]a=new int[N+1];for(a[1]=0,i=2;i<=N;i++){a[i]=1;}
for(i=2;i<=N/2;i++){for(j=2;j<=N/i;j++){a[i*j]=0;}
System.out.println(i+"の倍数をふるいにかけた直後の配列aの状態");
for(j=1;j<=N;j++)System.out.print(a[j]+" ");System.out.println();}
for(i=1;i<=N;i++){if(a[i]>0){System.out.print(i+" ");}}
System.out.println();}}