1 #include <iostream> 2 using namespace std; 3   4 int main() 5 { 6     long num; 7       8     while(cin >> num){ 9         if(num == 1){10             cout << num << endl;11             continue;12         }13          14         for(int i = 2; i <= num; ++i){15            if(num%i == 0){              16                num = num/i;17                cout << i << " ";18                i--;//遇到一个质数，那么该质数可能会被整除多次19            }          20         }21         cout << endl;       22     }   23      24     return 0;25 }