Compilare: user.cpp: In function ‘int main()’: user.cpp:27:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<s1.size();++j) ^ user.cpp:29:43: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(isalpha(s1[j]) && fol[s1[j]]==0) ^ user.cpp:32:26: warning: array subscript has type ‘char’ [-Wchar-subscripts] fol[s1[j]]=1; ^ user.cpp:35:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<s2.size();++j) ^ user.cpp:37:44: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(isalpha(s2[j]) && fol2[s2[j]]==0) ^ user.cpp:40:27: warning: array subscript has type ‘char’ [-Wchar-subscripts] fol2[s2[j]]=1; ^ user.cpp:50:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k=0;k<l1.size();++k) ^ user.cpp:52:47: warning: array subscript has type ‘char’ [-Wchar-subscripts] if((j&(1<<k))==0)ind[l1[k]]=0; ^ user.cpp:53:35: warning: array subscript has type ‘char’ [-Wchar-subscripts] else ind[l1[k]]=1; ^ user.cpp: In function ‘int op4()’: user.cpp:124:29: warning: array subscript has type ‘char’ [-Wchar-subscripts] r=ind[s[poz]]; ^