Compilare: main.cpp: In function 'bool factor()': main.cpp:56:17: warning: array subscript has type 'char' [-Wchar-subscripts] 56 | r=e[s[i]]; | ^ main.cpp: In function 'int main()': main.cpp:69:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 69 | for(int i=0; i<c.size(); i++) | ~^~~~~~~~~ main.cpp:78:11: warning: array subscript has type 'char' [-Wchar-subscripts] 78 | e[ch]=e[ch]^1; | ^~ main.cpp:78:17: warning: array subscript has type 'char' [-Wchar-subscripts] 78 | e[ch]=e[ch]^1; | ^~