In file included from /usr/include/c++/4.4/unordered_set:35, from string.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. string.cpp: In function 'int cauta(std::vector<int, std::allocator<int> >*, int)': string.cpp:34: warning: comparison between signed and unsigned integer expressions string.cpp:32: warning: unused variable 'gasit' string.cpp: In function 'int main()': string.cpp:104: warning: unused variable 'i' string.cpp:97: warning: unused variable 'ok'