Compilare: user.cpp: In function ‘int main()’: user.cpp:29:52: warning: array subscript has type ‘char’ [-Wchar-subscripts] for(i=0;i<n;++i) update(s[i]-'a'+1,1),++freq[s[i]]; ^ user.cpp:32:34: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(query(s[i]-'a') && freq[s[i]]>1) --freq[s[i]],update(s[i]-'a'+1,-1); ^ user.cpp:32:50: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(query(s[i]-'a') && freq[s[i]]>1) --freq[s[i]],update(s[i]-'a'+1,-1); ^ user.cpp:33:20: warning: array subscript has type ‘char’ [-Wchar-subscripts] else if(freq[s[i]]) cout<<s[i],update(s[i]-'a'+1,freq[s[i]]),freq[s[i]]=0; ^ user.cpp:33:61: warning: array subscript has type ‘char’ [-Wchar-subscripts] else if(freq[s[i]]) cout<<s[i],update(s[i]-'a'+1,freq[s[i]]),freq[s[i]]=0; ^ user.cpp:33:73: warning: array subscript has type ‘char’ [-Wchar-subscripts] else if(freq[s[i]]) cout<<s[i],update(s[i]-'a'+1,freq[s[i]]),freq[s[i]]=0; ^