Compilare: main.cpp: In function 'std::string caps(std::string)': main.cpp:11:21: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 11 | for (int i = 0; i < s.size(); i++) { | ~~^~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:35:17: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 35 | for (i = 0; i < sn.size(); i++) { | ~~^~~~~~~~~~~ main.cpp:36:12: warning: array subscript has type 'char' [-Wchar-subscripts] 36 | f[sn[i]]++; | ^ main.cpp:83:14: warning: array subscript has type 'char' [-Wchar-subscripts] 83 | sum *= f[ch]; | ^~