Code to implement a command-line search auto complete interface won't work, whats the problem?   #include #include #include #include   const int ALPHABET_SIZE = 28;   class Trie { private: structTrieNode { //Node struct which contains a a child node for each letter of the alphabet TrieNode *children[ALPHABET_SIZE]; boolisEndOfWord;//bool to determine if letter is the last in a word   TrieNode() {//constructor to initially set every child node to empty, and bool to false for (int i = 0; i < ALPHABET_SIZE; i++) { children[i] = NULL; } isEndOfWord = false; }   ~TrieNode() {//deconstructor for (int i = 0; i < ALPHABET_SIZE; i++) { if (children[i] != NULL) { deletechildren[i]; } } } };   TrieNode *root;//pointer to point to first letter in word   public: Trie() { root = newTrieNode(); //new node is created for first letter inserted }   ~Trie() { deleteroot; }   //this function inserts every word in the dictionary to the trie to create a path from first letter to last letter. //make root=first letter, see if the next letter exists as a child of root, if it doesnt create it, and move current to the next letter in word   voidinsert(const std::string &word) { TrieNode *current = root;//pointer to point to current letter, which begins at root node(bc its the first letter) for (char c : word) { int index; if(c=='_'){ index = ALPHABET_SIZE - 1; } else{ index = c - 'a'; }   if (current->children[index] == NULL) {//check if the next letter in the word currently exists as a child of the current node current->children[index] = new TrieNode();//if it doesnt create a new node and assign it to the child(next letter) } current = current->children[index];//make current the node it was pointing to(next letter). now the current node is the next letter } current->isEndOfWord = true;//after looping through each letter, current points to last letter so change its bool to true }   boolsearch(const std::string &word) { TrieNode *current = root; for (char c : word) { int index; if(c=='_'){ index=ALPHABET_SIZE -1; } else{ index=c-'a'; }   if (current->children[index] == NULL) { returnfalse;//if the next letter isnt a child of current node, return false akatheres no more searching to be done } current = current->children[index]; } return current->isEndOfWord;//if we get all the way through the search word without returning false, signal the last letter as the end of the word. }   std::vector autocomplete(const std::string &prefix) { std::vector results; TrieNode *current = root; //the user input will be stored in prefix.   //traverse the tree to see if each letter in prefix lines with with a word //functions similarly to search function but traverses user input instead of dictionary word and doesnt alter the isendofwordbool for (char c : prefix) { int index; if(c=='_'){ index=ALPHABET_SIZE-1; } else{ index=c-'a'; }   if (current->children[index] == NULL) { return results; } current = current->children[index]; }   //if we makeit through the loop that means there is a path in tree the aligns with user input prefix. //current will now be pointing to the last letter in the prefix   dfs(current, prefix, results);   return results; } private: //function for depth first search. //from the starting letter, it looks at input, checks if the full input is a word     voiddfs(TrieNode *node, const std::string &prefix, std::vector &results) { if (node->isEndOfWord) { results.push_back(prefix);//checks if full prefix input is a word, and if it is adds it to the result vector } for (int i = 0; i < ALPHABET_SIZE; i++) { if (node->children[i] != NULL) {//for each letter in alphabet check if the current node has that letter as a child char c = i + 'a';//if it does exist, assign that letter to char c, add it to the prefix, and redo the traversal dfs(node->children[i], prefix + c, results); } } } }; int main() { Trie trie;   std::ifstream file("Dictionary.txt"); if (file.is_open()) { std::string word; while (file >> word) { trie.insert(word); } file.close(); }   std::cout << "Type your search:\n"; std::string query; while (std::getline(std::cin, query)) { std::vector options = trie.autocomplete(query); std::cout << "Possible searches include: "; for (int i = 0; i < options.size(); i++) { std::cout << options[i]; if (i != options.size() - 1) { std::cout << ", "; } } std::cout << '\n'; std::cout << "Please type your search: \n";   }   return 0; }