线性筛素数

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <math.h>

const int N = 10000000;
bool a[N];
int p[N];
using namespace std;

void debug( )
{
 #ifdef P
 freopen("out","w",stdout);
 #endif
 }
 
void prime( )
{   
    debug( );
    memset(a, 0, N*sizeof(a[0]));
    int num = 0, i, j;
    for (i = 2; i < N; ++i) {
        if( a[i] == 0 ) p[num++] = i;
        for (j = 0; (j < num && i*p[j] < N); ++j) {
            a[ i * p[j] ] = 1;
            if(i%p[j] == 0) break;
        }
    }
}

int main( )
{
    int i;
    prime( );
    for (i = 0; i < 1000000; i++)
        printf("%d\n",p[i]);
    return 0;
}