题解 | #质数因子#

#include <iostream>
#include <cmath>
using namespace std;

int main()
{
    int num;
    cin >> num;
    while (num != 1)
    {
        for (int i = 2; i <= num; i++)
        {
            if (i > sqrt(num))  //大于平方根则只有数本身为质因数
                i = num;
            if (num % i == 0)
            {
                cout << i;
                num /= i;
                if (num != 1)   //若未找完则输出空格
                    cout << " ";
                break;          //当找到质因数时，重新开始下个循环
            }
        }
    }
    return 0;
}