Compilare: user.cpp: In function ‘int main()’: user.cpp:12:9: warning: suggest parentheses around ‘+’ inside ‘>>’ [-Wparentheses] f>>s+1; ^ user.cpp:14:15: warning: array subscript has type ‘char’ [-Wchar-subscripts] fr[s[i]]++; ^ user.cpp:16:20: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(viz[s[i]]==0){ ^ user.cpp:17:47: warning: array subscript has type ‘char’ [-Wchar-subscripts] while(vf>0&&st[vf]>s[i]&&fr[st[vf]]>0){ ^ user.cpp:18:27: warning: array subscript has type ‘char’ [-Wchar-subscripts] viz[st[vf]]=0; ^ user.cpp:23:21: warning: array subscript has type ‘char’ [-Wchar-subscripts] viz[s[i]]=1; ^ user.cpp:26:18: warning: array subscript has type ‘char’ [-Wchar-subscripts] fr[s[i]]--; ^