Compilare: user.cpp: In function ‘int main()’: user.cpp:127:14: warning: array subscript has type ‘char’ [-Wchar-subscripts] vf[v[i]]++; ^ user.cpp:128:18: warning: array subscript has type ‘char’ [-Wchar-subscripts] vec[vf[v[i]]].first=v[i]; ^ user.cpp:129:18: warning: array subscript has type ‘char’ [-Wchar-subscripts] vec[vf[v[i]]].second=i; ^ user.cpp: In function ‘char nextch()’: user.cpp:9:29: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buf,1,MAXBUF,fi); ^