도도의 초록누리

#include <iostream>

using namespace std;

int sum(int n);
int main(){

    cout << sum(10) << endl;
}

int sum(int n){

    if ( n == 1 ){
        return 1;
    }
    else{
        return sum(n-1) + n;
    }
}

#include <iostream>
#include <string>
#include <vector>
#include <math.h>

using namespace std;

vector<int> solution(long long n) {
    vector<int> answer;
    string strNumber;

    long long conversionNumber;
    int div = 10;
    int size = 0;
    int tmp = n;

    while (tmp > 0) {

        tmp = tmp / 10;
        size++;
    }

    strNumber = to_string(n);

    while (size > 0) {

        conversionNumber = std::stoll(strNumber.substr((size - 1), 1));
        //cout << strNumber.substr( (size - 1), 1) << endl;
        answer.push_back(conversionNumber);
        size--;
    }

    return answer;
}

int main() {

    solution(12345);

}