Compilare: main.cpp: In constructor 'Trie::Trie()': main.cpp:27:38: warning: passing NULL to non-pointer argument 2 of 'void* memset(void*, int, size_t)' [-Wconversion-null] memset(son, NULL, sizeof(son)); ^ main.cpp: In function 'void add(Trie*, int, const string&)': main.cpp:35:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(pos == s.size()) ~~~~^~~~~~~~~~~ main.cpp:39:25: warning: array subscript has type 'char' [-Wchar-subscripts] if(node -> son[c] == NULL) ^ main.cpp:40:26: warning: array subscript has type 'char' [-Wchar-subscripts] node -> son[c] = new Trie(); ^ main.cpp:42:26: warning: array subscript has type 'char' [-Wchar-subscripts] add(node -> son[c], pos + 1, s); ^ main.cpp: In function 'void del(Trie*, int, const string&)': main.cpp:48:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(pos == s.size()) ~~~~^~~~~~~~~~~ main.cpp:52:26: warning: array subscript has type 'char' [-Wchar-subscripts] del(node -> son[c], pos + 1, s); ^ main.cpp: In function 'int query2(Trie*, int, const string&)': main.cpp:57:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(pos == s.size()) ~~~~^~~~~~~~~~~ main.cpp:61:21: warning: array subscript has type 'char' [-Wchar-subscripts] if(node -> son[c] == NULL) ^ main.cpp:63:32: warning: array subscript has type 'char' [-Wchar-subscripts] return query2(node -> son[c], pos + 1, s); ^ main.cpp: In function 'int query3(Trie*, int, const string&)': main.cpp:67:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(pos == s.size()) ~~~~^~~~~~~~~~~ main.cpp:71:21: warning: array subscript has type 'char' [-Wchar-subscripts] if(node -> son[c] == NULL) ^ main.cpp:74:21: warning: array subscript has type 'char' [-Wchar-subscripts] if(node -> son[c] -> pref == 0) ^ main.cpp:76:32: warning: array subscript has type 'char' [-Wchar-subscripts] return query3(node -> son[c], pos + 1, s); ^