Compilare: user.cpp: In constructor ‘Trie::Trie()’: user.cpp:37:42: warning: passing NULL to non-pointer argument 2 of ‘void* memset(void*, int, size_t)’ [-Wconversion-null] memset(child, NULL, sizeof(child)); ^ user.cpp: In function ‘void pushToTrie(Trie*, int)’: user.cpp:44:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (letter == str.size()) { ^ user.cpp: In function ‘bool popFromTrie(Trie*, int)’: user.cpp:57:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (letter == str.size()) { ^ user.cpp: In function ‘int getNumberOfWords(Trie*, int)’: user.cpp:79:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (letter == str.size()) ^ user.cpp: In function ‘int getNumberOfPrefixes(Trie*, int)’: user.cpp:90:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (letter == str.size() || word->child[str[letter] - 'a'] == NULL) ^