Compilare: user.cpp: In function ‘int main()’: user.cpp:20:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<word.size();++i){ ^ user.cpp:21:30: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(!frecv[word[i]] and word[i]!='.'){ ^ user.cpp:23:30: warning: array subscript has type ‘char’ [-Wchar-subscripts] frecv[word[i]]=1; ^ user.cpp:34:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<list[n].size();++i)fout<<list[n][i]<<' '; ^