#include <string>
#include <vector>

using namespace std;

void tokenize(const string& str,
                    vector<string>& tokens,
                    const string& delimiters = " ") {
    string::size_type lastPos = str.find_first_not_of(delimiters, 0);
    string::size_type pos     = str.find_first_of(delimiters, lastPos);

    while (string::npos != pos || string::npos != lastPos) {
        tokens.push_back(str.substr(lastPos, pos - lastPos));
        lastPos = str.find_first_not_of(delimiters, pos);
        pos = str.find_first_of(delimiters, lastPos);
    }
}