Compilare: user.cpp: In function ‘int main()’: user.cpp:21:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0; i<a.size(); ++i) ^ user.cpp:24:22: warning: array subscript has type ‘char’ [-Wchar-subscripts] viz[i]=viz1[c]+1; ^ user.cpp:26:28: warning: array subscript has type ‘char’ [-Wchar-subscripts] father[i]=father1[c]; ^ user.cpp:29:26: warning: array subscript has type ‘char’ [-Wchar-subscripts] if (viz[i]>viz1[c]) ^ user.cpp:31:23: warning: array subscript has type ‘char’ [-Wchar-subscripts] viz1[c]=viz[i]; ^ user.cpp:32:26: warning: array subscript has type ‘char’ [-Wchar-subscripts] father1[c]=i; ^