Compilare: user.cpp: In function ‘std::string com(std::string, std::string)’: user.cpp:11:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0 ; i < x.size() ; i ++){ ^ user.cpp: In function ‘int main()’: user.cpp:38:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (s[i].size() > mn){ ^ user.cpp:47:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (s[i].size()==mn && i!=j){ ^ user.cpp: In function ‘std::string com(std::string, std::string)’: user.cpp:23:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:47:29: warning: ‘j’ may be used uninitialized in this function [-Wmaybe-uninitialized] if (s[i].size()==mn && i!=j){ ^