Compilare: user.cpp: In function ‘std::vector<std::pair<int, int>, std::allocator<std::pair<int, int> > > ic(std::vector<std::pair<int, int>, std::allocator<std::pair<int, int> > >, int)’: user.cpp:26: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:51: warning: comparison between signed and unsigned integer expressions user.cpp:52: warning: comparison between signed and unsigned integer expressions