题解 | #质数因子#

#include<iostream>
#include<math.h>
using namespace std;
 
int main()
{
    long n, old_n=0;
    cin >> n;
    while (n != 1)
    {
        for (int i = 2; i <=sqrt((double)n); i++) //不要忽视“=”符号，很重要！
        {
            old_n = n;
            while (n % i == 0) {
                cout << i << " ";
                n /= i;
            }
            if (old_n != n)
                break;
        }
        if (old_n == n)
        {
            cout << n << ' ';
			n/=n;
        }
    }
	return 0;
}