C++ program

#include <iostream>
#include <vector>
#include <sstream>
using namespace std;
int main() {
    string line;
    getline(cin, line);
    istringstream input(line);
    int val, sum = 0, count = 0;
    vector<char> v;
    char ch;
    while(input >> ch) {
        v.push_back(ch);
//      cout << ch << " ";
    }
    for(int i = 0 ; i < v.size() ; ++i)
    {
        if(isalpha(v[i])) {
            cout << "Invalid Input" << endl;
            return 0;
            //sum += (v[i] - '0');
        }
        else{
            sum += (v[i] - '0');
        }
    }
    cout << sum << endl;
    return 0;
}