In file included from /usr/include/c++/4.4/unordered_map:35, from guess.cpp:2: /usr/include/c++/4.4/c++0x_warning.h:31:2: error: #error This file requires compiler and library support for the upcoming ISO C++ standard, C++0x. This support is currently experimental, and must be enabled with the -std=c++0x or -std=gnu++0x compiler options. guess.cpp:8: error: expected constructor, destructor, or type conversion before '<' token guess.cpp: In function 'void read()': guess.cpp:33: error: 'a' was not declared in this scope guess.cpp: In function 'void DFS(int)': guess.cpp:46: warning: 'auto' will change meaning in C++0x; please remove it guess.cpp:46: error: expected initializer before ':' token guess.cpp:74: error: expected primary-expression at end of input guess.cpp:74: error: expected ';' at end of input guess.cpp:74: error: expected primary-expression at end of input guess.cpp:74: error: expected ')' at end of input guess.cpp:74: error: expected statement at end of input guess.cpp:74: error: expected '}' at end of input