Compilare: user.cpp: In function ‘int main()’: user.cpp:12:10: warning: array subscript has type ‘char’ [-Wchar-subscripts] fr[ch]++; ^ user.cpp:20:12: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(fr[ch]>=nr/2+1) ^ user.cpp:26:14: warning: array subscript has type ‘char’ [-Wchar-subscripts] {if(fr[ch]>0&&ch!=ch1) ^ user.cpp:32:12: warning: array subscript has type ‘char’ [-Wchar-subscripts] fr[ch2]--; ^ user.cpp:38:10: warning: array subscript has type ‘char’ [-Wchar-subscripts] fr[ch]--; ^