Compilare: user.cpp: In function ‘int main()’: user.cpp:22:9: warning: array subscript has type ‘char’ [-Wchar-subscripts] f[s[i]]++; ^ user.cpp:25:9: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(f[c]) ^ user.cpp:36:13: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(f[s[i]] > 0) { ^ user.cpp:40:14: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(f[s[i]] == 1) ^ user.cpp:48:10: warning: array subscript has type ‘char’ [-Wchar-subscripts] f[s[i]]--; ^ user.cpp:50:12: warning: array subscript has type ‘char’ [-Wchar-subscripts] f[s[next]] = 0; ^ user.cpp:29:6: warning: unused variable ‘cnt’ [-Wunused-variable] int cnt = 0; ^