Compilare: user.cpp: In function ‘int main()’: user.cpp:13:11: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(fr[c[i]]==0) kk++; ^ user.cpp:14:8: warning: array subscript has type ‘char’ [-Wchar-subscripts] fr[c[i]]++; ^ user.cpp:17:12: warning: array subscript has type ‘char’ [-Wchar-subscripts] fr[c[i-l+1]]--;if(fr[c[i-l+1]]==0)kk--;l--;} ^ user.cpp:17:30: warning: array subscript has type ‘char’ [-Wchar-subscripts] fr[c[i-l+1]]--;if(fr[c[i-l+1]]==0)kk--;l--;} ^