In file included from /usr/include/c++/4.4/unordered_map:35, from patrate4.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. patrate4.cpp:7: error: expected constructor, destructor, or type conversion before '<' token patrate4.cpp: In function 'int main()': patrate4.cpp:23: error: 'fr' was not declared in this scope patrate4.cpp:46: error: 'fr' was not declared in this scope patrate4.cpp:10: warning: unused variable 'st' patrate4.cpp:10: warning: unused variable 'dr'