Compilare: user.cpp: In function ‘int main()’: user.cpp:16:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<s.size();++i) ^ user.cpp:18:21: warning: array subscript has type ‘char’ [-Wchar-subscripts] if (!fv[s[i]])++ct; ^ user.cpp:19:18: warning: array subscript has type ‘char’ [-Wchar-subscripts] ++fv[s[i]]; ^ user.cpp:24:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0;j<s.size();++j) ^ user.cpp:26:22: warning: array subscript has type ‘char’ [-Wchar-subscripts] --fv[s[j]]; ^ user.cpp:27:25: warning: array subscript has type ‘char’ [-Wchar-subscripts] if (!fv[s[j]] && !vf[s[j]]) ^ user.cpp:27:38: warning: array subscript has type ‘char’ [-Wchar-subscripts] if (!fv[s[j]] && !vf[s[j]]) ^ user.cpp:32:54: warning: array subscript has type ‘char’ [-Wchar-subscripts] if (s[j]<mini && !vf[s[j]]) ^ user.cpp:34:38: warning: array subscript has type ‘char’ [-Wchar-subscripts] ++fv[s[j]]; ^ user.cpp:37:28: warning: array subscript has type ‘char’ [-Wchar-subscripts] vf[mini]=1; ^ user.cpp:39:34: warning: array subscript has type ‘char’ [-Wchar-subscripts] --fv[s[j]],s[j]='z'+1; ^