vector<vector<int>> Prior to C++11, the code above would fail to compile. The lexer would see the final ">>" and assume it was the out-stream operator. This wa

vector<vector<int>> Prior to C++11, the code above would fail to compile. The lexer would see the final ">>" and assume it was the out-stream operator. This was such an annoying issue that they eventually changed the grammar so that the above would compile as expected.