using templates with vectors and vector functions
std::vector<Word> concordance = push_vector(data);

template <typename T>
 std::vector<T> push_vector(std::string&);

main.cpp: In function ‘int main(int, char**)’:
main.cpp:27:53: error: no matching function for call to ‘push_vector(std::string&)’
main.cpp:27:53: note: candidate is:
templates.h:13:20: note: template<class T> std::vector<T> push_vector(std::string&)

template <typename T>
void push_vector(const std::string& str, std::vector<T>& vec)
{
   // convert str to T if possible
   // throw on failure maybe?
   // assign vec with converted data
}

std::string data("Hello");
std::vector<Word> concordance;
push_vector(data, concordance);

std::vector<Word> concordance = push_vector<Word>(data);