求n的所有素数

#include <iostream>
#include <vector>
using namespace std;
int main()
{
    int n;
    vector<int> restore;
    cin >> n;
    bool flag;
    for (size_t i = 2; i <= n; i++)
    {
        flag = true;
        for (size_t j = 2; j * j <= i; j++)
        {
            if (i%j == 0)
            {
                flag = false;
                break;
            }
        }
        if (flag)
        {
            restore.push_back(i);
        }
    }
    cout << n << "共有" << restore.size() << "个素数，分别为：\n";
    int blank = 0;
    for (const int i : restore)
    {
        //每打印十个数换行一次
        if (blank > 0 && blank % 10 == 0)
        {
            cout << endl;
        }
        cout << i << "\t";
    }

    system("pause");
    return 0;
}