Invalid input

#include <iostream>
#include <vector>
#include <string>
#include <sstream>
#include <algorithm>

int sumNumbers (std::vector <int> vec){

    int sum = 0;

    for(int number : vec){

        sum += number;
    }

    return sum;
}


std::vector <int> extractNums (std::string lineStr){


    std::istringstream istrLine(lineStr);
    std::vector <int> numbers;
    int foundNumb;
    std::string foundWords;

    while(!istrLine.eof()){

        istrLine >> foundWords;
        if(std::stringstream(foundWords) >> foundNumb){

            numbers.push_back(foundNumb) ;
            foundWords = "";
        }
    }

    return numbers;

}


int main(){

    std::string line;
    getline(std::cin,line);

    std::vector <int> numbers = extractNums(line);

    std::cout << sumNumbers(numbers) << std::endl;

    std::istringstream lineStrm(line);
    std::string words;
    std::string printWord;

    while(lineStrm >> words){

        if(isalpha(words[0])){

            printWord += words + " ";
        }
    }

    std::cout << printWord;

    return 0;
}