Compilare: main.cpp: In function 'int main()': main.cpp:15:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 15 | for(int i = 0; i < s.size()+3; i++){ | ~~^~~~~~~~~~~~ main.cpp:19:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 19 | for(int i = 1; i < s.size(); i++){ | ~~^~~~~~~~~~ main.cpp:21:29: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 21 | while(st >= 0 && dr < s.size() && s[st] == s[dr]){ | ~~~^~~~~~~~~~ main.cpp:27:29: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 27 | while(st >= 0 && dr < s.size() && s[st] == s[dr]){ | ~~~^~~~~~~~~~