Compilare: user.cpp: In function ‘int main()’: user.cpp:30:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(t.size() > max_size) ^ user.cpp:35:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] else if(t.size() == max_size) ^ user.cpp:79:49: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < interesante.size(); i++) ^ user.cpp: In function ‘bool is_substr(std::string, std::string)’: user.cpp:105:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < b.size(); i++) ^ user.cpp:109:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(k < a.size()) ^