欧拉筛

#include<iostream>
using namespace std;

#define MAX 10000

int flag[MAX];
int prime[MAX];
int primesize = 0;
int min_prime[MAX];


void getprime(int n)//n以内的素数
{
	for (int i = 2; i <= n; ++i)
	{
		if (flag[i] == 0)
			prime[primesize++] = i;
		for (int j = 0; j <= primesize; ++j)
		{
			if (i*prime[j] > n) break;
			flag[i*prime[j]] = 1;
			min_prime[i*prime[j]] = prime[j];
			if (i%prime[j] == 0) break;
		}
	}
}

int main()
{
	getprime(10000);
	for (int i = 0; i < primesize; ++i)
		cout << prime[i] << endl;
	system("pause");
	return 0;
}