素数筛选法

#include<stdio.h>#define N 10000000int Prime[N] = {1,1,};//标记是否为素数int main(){int i,j;for( i = 2; i < N; ++ i){if(!Prime[i]){for( j = 2; i * j < N; ++ j )Prime[i * j] = 1;}}return 0;}