Find end of first five cols

gistfile1.cpp

string::size_type p_last = str.find_first_not_of(" ", 0);
string::size_type p_curr = str.find_first_of(" ", p_last);

// seek to end of header columns (5)
for(int i = 0; i<4; ++i){
  p_last = str.find_first_not_of(" ", p_curr);
  p_curr = str.find_first_of(" ", p_last);
}

ss.str(line.substr(0, p_last + 1));