Compilare: main.cpp: In member function 'int Trie::change(int)': main.cpp:27:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(pos == s.size()) ~~~~^~~~~~~~~~~ main.cpp: In member function 'long long int Trie::get(int)': main.cpp:61:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(pos == s.size()) ~~~~^~~~~~~~~~~ main.cpp: At global scope: main.cpp:75:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type] main() ^