Compilare: user.cpp: In function ‘int main()’: user.cpp:32:9: warning: array subscript has type ‘char’ [-Wchar-subscripts] fb[a][b] = fb[b][a] = 1; ^ user.cpp:32:12: warning: array subscript has type ‘char’ [-Wchar-subscripts] fb[a][b] = fb[b][a] = 1; ^ user.cpp:32:20: warning: array subscript has type ‘char’ [-Wchar-subscripts] fb[a][b] = fb[b][a] = 1; ^ user.cpp:32:23: warning: array subscript has type ‘char’ [-Wchar-subscripts] fb[a][b] = fb[b][a] = 1; ^