Compilare: main.cpp: In function 'int main()': main.cpp:27:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 27 | for(i = 0; i < cuv.size(); i++) | ~~^~~~~~~~~~~~ main.cpp:28:28: warning: array subscript has type 'char' [-Wchar-subscripts] 28 | Fr[i] = (++f[cuv[i]]); | ^ main.cpp:38:16: warning: array subscript has type 'char' [-Wchar-subscripts] 38 | f1 = f[c]; | ^ main.cpp:39:20: warning: array subscript has type 'char' [-Wchar-subscripts] 39 | f2 = f[caps(c)]; | ~~~~^~~