笔记

#include <iostream>
using namespace std;

int main()
{
    int n; cin >> n;
    while (n --)
    {
        int x, flag = 0; cin >> x;
        for (int i = 2; i * i <= x; i ++)
        // 这里要注意 完全平方数 需要 <= 不然会漏掉
        {
            if (x % i == 0) 
            {
                flag = 1;
                break;
            }
        }

        if (flag == 1) cout << x << " is not prime" << endl;
        else cout << x << " is prime" << endl;
    }
}