// vertices, but deciding this is
// difficult and not implemented.
// for (unsigned int line=0; line<4; ++line)
-// if (needed_lines.find(make_pair(line_vertices[line].second,
-// line_vertices[line].first))
+// if (needed_lines.find(std::make_pair(line_vertices[line].second,
+// line_vertices[line].first))
// !=
// needed_lines.end())
// {
// // rotate vertex numbers
-// swap (cells[cell].vertices[0], cells[cell].vertices[2]);
-// swap (cells[cell].vertices[1], cells[cell].vertices[3]);
+// std::swap (cells[cell].vertices[0], cells[cell].vertices[2]);
+// std::swap (cells[cell].vertices[1], cells[cell].vertices[3]);
// // remake lines
// line_vertices[0]
-// = make_pair (cells[cell].vertices[0], cells[cell].vertices[1]);
+// = std::make_pair (cells[cell].vertices[0], cells[cell].vertices[1]);
// line_vertices[1]
-// = make_pair (cells[cell].vertices[1], cells[cell].vertices[2]);
+// = std::make_pair (cells[cell].vertices[1], cells[cell].vertices[2]);
// line_vertices[2]
-// = make_pair (cells[cell].vertices[0], cells[cell].vertices[3]);
+// = std::make_pair (cells[cell].vertices[0], cells[cell].vertices[3]);
// line_vertices[3]
-// = make_pair (cells[cell].vertices[3], cells[cell].vertices[2]);
+// = std::make_pair (cells[cell].vertices[3], cells[cell].vertices[2]);
// // allow for only one such
// // rotation
// break;