1 #include<iostream> 2 #include<stdio.h> 3 #include<cstring> 4 #include<cstdlib> 5 #include<bitset> 6 using namespace std; 7 const int maxn = 1e6; 8 bitset<maxn> prime; 9 10 void init()11 {12     int i,j;13     prime.set();14     for(i=4;i<=maxn;i=i+2)prime[i]=false;15     for(i=3;(j=i*i)<maxn;i=i+2)16     {17         if(prime[i]==false) continue;18         for(;j<maxn;j=j+i+i)19             prime[j]=false;20     }21 }22 int main()23 {24     init();25     for(int i=2;i<=100;i++)if(prime[i]==true) printf("%d ",i);26     return 0;27 }