Compilare: main.cpp: In function 'void add_string(const string&)': main.cpp:21:29: warning: array subscript has type 'char' [-Wchar-subscripts] if ( trie[i].link[it] == 0 ) { ^ main.cpp:22:28: warning: array subscript has type 'char' [-Wchar-subscripts] trie[i].link[it] = n; ^ main.cpp:25:28: warning: array subscript has type 'char' [-Wchar-subscripts] i = trie[i].link[it]; ^ main.cpp: In function 'void delete_string(const string&)': main.cpp:33:28: warning: array subscript has type 'char' [-Wchar-subscripts] i = trie[i].link[it]; ^ main.cpp: In function 'int string_appearances(const string&)': main.cpp:41:46: warning: array subscript has type 'char' [-Wchar-subscripts] while ( it != s.end() && trie[i].link[*it] != 0 ) { ^ main.cpp:42:29: warning: array subscript has type 'char' [-Wchar-subscripts] i = trie[i].link[*it]; ^ main.cpp: In function 'int longest_common_prefix(const string&)': main.cpp:54:29: warning: array subscript has type 'char' [-Wchar-subscripts] i = trie[i].link[*it]; ^ main.cpp:51:16: warning: unused variable 'maxim' [-Wunused-variable] int j = 0, maxim; ^~~~~ main.cpp: In function 'int main()': main.cpp:64:9: warning: unused variable 'i' [-Wunused-variable] int i, cer; ^