Compilare: user.cpp: In function ‘int main()’: user.cpp:76:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < comp.size(); ++i) ^ user.cpp:78:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < comp[i].size(); ++j) ^