Compilare: user.cpp: In function ‘void form_t(std::vector<int, std::allocator<int> >&, std::string)’: user.cpp:10: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:36: warning: comparison between signed and unsigned integer expressions user.cpp:40: warning: comparison between signed and unsigned integer expressions user.cpp:43: warning: comparison between signed and unsigned integer expressions user.cpp:43: warning: comparison between signed and unsigned integer expressions user.cpp:48: warning: comparison between signed and unsigned integer expressions user.cpp:57: warning: comparison between signed and unsigned integer expressions