Compilare: user.cpp: In function ‘bool cont(int, int)’: user.cpp:28:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k = 0; k < v[i].size(); k++) { ^ user.cpp:31:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(C == v[j].size()) ^ user.cpp: In function ‘std::string cmp(std::string&, std::string&)’: user.cpp:42:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < a.size(); i++) { ^ user.cpp: In function ‘int main()’: user.cpp:79:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < v[i].size(); j++) ^