Compilare: user.cpp: In function ‘int main()’: user.cpp:21:15: warning: array subscript has type ‘char’ [-Wchar-subscripts] last[ch[1]]=1; ^ user.cpp:26:22: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(last[ch[i]]==0) ^ user.cpp:29:23: warning: array subscript has type ‘char’ [-Wchar-subscripts] last[ch[i]]=i; ^ user.cpp:34:27: warning: array subscript has type ‘char’ [-Wchar-subscripts] pos=last[ch[i]]; ^ user.cpp:43:23: warning: array subscript has type ‘char’ [-Wchar-subscripts] last[ch[i]]=i; ^ user.cpp:13:28: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%c",&ch[1]); ^ user.cpp:17:32: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%c",&ch[n]); ^