Compilare: main.cpp: In function 'int main()': main.cpp:20:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 20 | for(int i = 0; i < s.size() - 1; i++) | ~~^~~~~~~~~~~~~~ main.cpp:21:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 21 | for(int j = 2; j < s.size() - 1; j++){ | ~~^~~~~~~~~~~~~~