Compilare: main.cpp: In function 'int main()': main.cpp:18:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 18 | for (int i = 0; i < text.size(); ++i) { | ~~^~~~~~~~~~~~~ main.cpp:19:21: warning: array subscript has type 'char' [-Wchar-subscripts] 19 | ++fr[text[i]]; | ^ main.cpp:25:29: warning: array subscript has type 'char' [-Wchar-subscripts] 25 | --fr[text[i - 7]]; | ^