https://school.programmers.co.kr/learn/courses/30/lessons/120851
using System;
public class Solution {
public int solution(string my_string) {
int answer = 0;
char[] my_char = my_string.ToCharArray();
for(int i=0; i<my_char.Length; i++){
//10진수인지 판별
if(Char.IsDigit(my_char[i])){
answer += (int)my_char[i]-48;
}
}
return answer;
}
}