In file included from /usr/include/c++/4.4/unordered_map:35, from johnie.cpp:5: /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. johnie.cpp:14: error: expected constructor, destructor, or type conversion before '<' token johnie.cpp: In function 'void df(int)': johnie.cpp:20: error: 'l' was not declared in this scope johnie.cpp:24: warning: 'auto' will change meaning in C++0x; please remove it johnie.cpp:24: error: ISO C++ forbids declaration of 'it' with no type johnie.cpp: In function 'int main()': johnie.cpp:37: error: 'l' was not declared in this scope johnie.cpp:54: warning: comparison between signed and unsigned integer expressions johnie.cpp:57: warning: comparison between signed and unsigned integer expressions