Compilare: user.cpp: In function ‘size_t count_frac(std::vector<std::vector<int, std::allocator<int> >*, std::allocator<std::vector<int, std::allocator<int> >*> >&, frac, int)’: user.cpp:37: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:108: warning: comparison between signed and unsigned integer expressions user.cpp:110: warning: comparison between signed and unsigned integer expressions