Compilare: user.cpp: In function ‘int main()’: user.cpp:20:15: warning: array subscript has type ‘char’ [-Wchar-subscripts] last[ch[1]]=1; ^ user.cpp:25:22: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(last[ch[i]]==0) ^ user.cpp:28:23: warning: array subscript has type ‘char’ [-Wchar-subscripts] last[ch[i]]=i; ^ user.cpp:33:27: warning: array subscript has type ‘char’ [-Wchar-subscripts] pos=last[ch[i]]; ^ user.cpp:42:23: warning: array subscript has type ‘char’ [-Wchar-subscripts] last[ch[i]]=i; ^ user.cpp:15:32: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%c",&ch[n]); ^