main.cpp

#include <iostream>
using namespace std;
#define MAX_N 100000001

int prime[MAX_N];
bool is_prime[MAX_N + 1];

int sieve(int n) {
  int p = 0;
  for (int i(0);i<=n;i++) is_prime[i] = true;
  is_prime[0] = is_prime[1] = false;
  for (int i(2);i<=n;i++){
    if (is_prime[i]){
      cout << i << ",";
      prime[p++] = i;
      for (int j(2*i);j<=n;j+=i) is_prime[j] = false;
    }
  }
  cout << endl;
  return p;
}
int main(){
  int N = 100000000;
  cout << N << "以下の素数を列挙" << endl;
  int cnt = sieve(N);
  cout << N << "以下の素数の個数:" << cnt << endl;
  return 0;
}