Compilare: main.cpp: In function 'void add(trie*, int, int)': main.cpp:25:12: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 25 | if (pos==s.size()) { | ~~~^~~~~~~~~~ main.cpp: In function 'void pop(trie*, int, int)': main.cpp:46:12: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 46 | if (pos==s.size() || parent->fiu[s[pos]-'a']==0) { | ~~~^~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:65:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 65 | for (int j=0;j<s.size();j++) | ~^~~~~~~~~ main.cpp:71:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 71 | for (int j=0;j<s.size()-1 && ctr>0;j++) { | ~^~~~~~~~~~~