Compilare: main.cpp: In function 'int main()': main.cpp:60:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 60 | for (int j = 0; j <= s.size(); j++) { | ~~^~~~~~~~~~~ main.cpp:61:13: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 61 | if (j == s.size()) { | ~~^~~~~~~~~~~ main.cpp:67:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 67 | for (int k = 0; k < s.size() - j - 1; k++) | ~~^~~~~~~~~~~~~~~~~~