Compilare: main.cpp: In function 'bool factor()': main.cpp:120:26: warning: array subscript has type 'char' [-Wchar-subscripts] r = fr[var[0]]; ^ main.cpp: In function 'int main()': main.cpp:143:20: warning: array subscript has type 'char' [-Wchar-subscripts] fr[variable] = !fr[variable]; ^ main.cpp:143:36: warning: array subscript has type 'char' [-Wchar-subscripts] fr[variable] = !fr[variable]; ^