Compilare: main.cpp: In function 'void rec(int)': main.cpp:13:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 13 | if(cs!=s && k==s.size()) | ~^~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:43:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 43 | for(int i=0; i<s.size(); i++) | ~^~~~~~~~~