const std::string& delimiters) {
std::string::size_type lastPos = str.find_first_not_of(delimiters,0);
std::string::size_type pos = str.find_first_of (delimiters,lastPos);
const std::string& delimiters) {
std::string::size_type lastPos = str.find_first_not_of(delimiters,0);
std::string::size_type pos = str.find_first_of (delimiters,lastPos);
tokens.push_back(str.substr(lastPos, pos - lastPos));
lastPos = str.find_first_not_of(delimiters, pos);
pos = str.find_first_of (delimiters, lastPos);
tokens.push_back(str.substr(lastPos, pos - lastPos));
lastPos = str.find_first_not_of(delimiters, pos);
pos = str.find_first_of (delimiters, lastPos);