#include <stdio.h> |
#include <stdlib.h> |
#define N 1000 |
int main ( void ) |
{ |
int i, j; |
int prime[N+1]; |
for ( i = 2; i <= N; i++ ) |
prime[i] = 1; |
for ( i = 2; i*i <= N; i++ ) // 这边可以改进 |
{ |
if ( prime[i] == 1 ) |
{ |
for ( j = 2*i; j <= N; j++ ) |
{ |
if ( j % i == 0 ) |
prime[j] = 0; |
} |
} |
} |
for ( i = 2; i < N; i++ ) |
{ |
if ( prime[i] == 1 ) |
{ |
printf ( "%4d " , i ); |
if ( i % 16 == 0 ) |
printf ( "\n" ); |
} |
} |
printf ( "\n" ); |
return 0; |
} |