Compilare: user.cpp: In function ‘int main()’: user.cpp:27:24: warning: array subscript has type ‘char’ [-Wchar-subscripts] exists[s[i]]=1; ^ user.cpp:29:27: warning: array subscript has type ‘char’ [-Wchar-subscripts] frecv[s[i]]++; ^ user.cpp:31:27: warning: array subscript has type ‘char’ [-Wchar-subscripts] frecv[s[i]]--; ^ user.cpp:37:27: warning: array subscript has type ‘char’ [-Wchar-subscripts] frecv[s[i]]++; ^ user.cpp:39:27: warning: array subscript has type ‘char’ [-Wchar-subscripts] frecv[s[i]]--; ^ user.cpp:40:24: warning: array subscript has type ‘char’ [-Wchar-subscripts] exists[s[i]]=1; ^ user.cpp:57:21: warning: array subscript has type ‘char’ [-Wchar-subscripts] if (exists[j]==1) ^ user.cpp:58:34: warning: array subscript has type ‘char’ [-Wchar-subscripts] fout<<j<<" "<<frecv[j]<<"\n"; ^