title: sorting vector of vector of strings in C++
body: <p>I am having trouble to figure out, how to sort a vector of vector of strings, here is the testing code.<br></p>
  
  <pre>
  <code>
  #include &ltiostream>
  #include &ltvector>
  #include &ltboost/algorithm/string.hpp>
  
  int main(int argc, char** argv) {
    std::vector &ltstd::vector &ltstd::string> > data_var;
    std::vector &ltstd::string> temp;
  
    std::string str1 = "1,hello3,temp2";
    std::string str2 = "2,hello2,temp1";
    std::string str3 = "3,hello1,temp3";
  
    boost::split(temp, str1, boost::is_any_of(","));
    data_var.push_back(temp);
    boost::split(temp, str2, boost::is_any_of(","));
    data_var.push_back(temp);
    boost::split(temp, str3, boost::is_any_of(","));
    data_var.push_back(temp);
  
    // sorting code here...
  }
  </code></pre>
  
  <p>Thanks in advance...</p>