Compilare: main.cpp: In function 'int main()': main.cpp:13:17: warning: array subscript has type 'char' [-Wchar-subscripts] f[ v[i] ]++; ^ main.cpp:14:22: warning: array subscript has type 'char' [-Wchar-subscripts] if ( f[ v[i] ] == 1 ) ^ main.cpp:17:21: warning: array subscript has type 'char' [-Wchar-subscripts] f[ v[k] ]--; ^ main.cpp:18:26: warning: array subscript has type 'char' [-Wchar-subscripts] if ( f[ v[k] ] == 0 ) ^