sieve.cpp

#include <bits/stdc++.h>
#include <sstream>

using namespace std;

void generate_sieve(int n){
	bool isPrime[n + 1];
	memset(isPrime, 1, sizeof(isPrime));

	isPrime[0] = 0;
	isPrime[1] = 0;
	isPrime[2] = 1;

	for (int i = 2 ; i <= n ; i ++ ){
		if (isPrime[i]) {
			for (int j = 2 ; i * j <= n ; j ++ ) {
				isPrime[i * j] = 0;
			}
		}
	}
}


int main(int argc, char** argv){
	stringstream sn(argv[1]);
	int n;
	sn >> n;
	generate_sieve(n);
	return 0;
}