Compilare: main.cpp: In function 'bool factor()': main.cpp:28:19: warning: array subscript has type 'char' [-Wchar-subscripts] 28 | nr = val[s[ind]]; | ~~~~~^ main.cpp: In function 'int main()': main.cpp:106:9: warning: array subscript has type 'char' [-Wchar-subscripts] 106 | val[ch] = !val[ch]; | ^~ main.cpp:106:20: warning: array subscript has type 'char' [-Wchar-subscripts] 106 | val[ch] = !val[ch]; | ^~ main.cpp:62:13: warning: unused variable 't' [-Wunused-variable] 62 | int n, i, t; | ^