分解素因数

#include <stdio.h>
#include <iostream>
#include <math.h>

using namespace std;

bool is_prime(int num)
{
    if (num < 2) return false;
    for (int i = 2; i < num; i++){
        if (num % i == 0)
            return false;
    }
    return true;
}

int main(void)
{
    int number;
    cin >> number;
    
    if (number < 2) {
        cout << "Please give a number bigger than 2" << endl;
        return 0;
    }

    if (is_prime(number)){
        cout << number << endl;
        return 0;
    }

    int prime_list[1000] = {0};
    int prime_count = 0;
    for (int i = 2; i <= number; i++){
        if (is_prime(i)){
            prime_list[++prime_count] = i;
        } 
    }

    int factor_list[1000] = {0};
    int factor_count = 0;

    int number_divided = number;

    int i = 1;
    while (number_divided != 1){
        int divider = prime_list[i];

        while(true){
            if (number_divided % divider == 0){
                factor_list[++factor_count] = divider;
                number_divided /= divider;
            } else {
               i++; 
               break;
            }
        }
    }

    for (int i = 1; i <= factor_count; i++){
        cout << factor_list[i] << ' '; 
    }
    cout << endl;
    return 0;
}