Compilare: main.cpp: In function 'int main()': main.cpp:50:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 50 | for (i = 1; i <= s.size(); i++) | ~~^~~~~~~~~~~ main.cpp:68:11: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 68 | if (k == s.size() - 1) | ~~^~~~~~~~~~~~~~~ main.cpp:44:15: warning: unused variable 'j' [-Wunused-variable] 44 | int k, i, j; | ^