In file included from /usr/include/c++/4.4/unordered_map:35, from showroom.cpp:4: /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. showroom.cpp:19: error: expected constructor, destructor, or type conversion before '<' token showroom.cpp: In function 'int main()': showroom.cpp:74: error: 'Hash' was not declared in this scope showroom.cpp:78: error: 'Hash' was not declared in this scope showroom.cpp:81: error: 'Hash' was not declared in this scope showroom.cpp:89: error: 'Hash' was not declared in this scope showroom.cpp:93: error: 'Hash' was not declared in this scope showroom.cpp:96: error: 'Hash' was not declared in this scope showroom.cpp:127: warning: comparison between signed and unsigned integer expressions showroom.cpp:137: warning: comparison between signed and unsigned integer expressions