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7/23/2019 autocomplete

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#include #include #include #include #include #include

using namespace std;

#define NR 27 // the American alphabet(26 letters) plus blank.

typedef struct TrieNode{bool NotLeaf; // indicates if the TrieNode struct is a leaf o

r an intern nodeTrieNode *pChildren[NR]; // a list of pointers corresponding to the used

alphabetchar word[20]; // the string stored in node

};

//function for creating a leaf nodeTrieNode *NewLeaf(char keyWord[20]){

TrieNode *node;int count;

//allocating the necessary memorynode = (TrieNode *)malloc(sizeof(TrieNode));

for(count = 0; count < 27; count++) //the terminal nodes don't have children

node->pChildren[count] = NULL;node->NotLeaf = false; // the node is a leaf

strcpy(node->word,keyWord); //store in the structure(node->word) the string

return node;

}

//function for creating a intern nodeTrieNode *NewIntern(){

TrieNode *node;int count;

//allocating the necessary memorynode = (TrieNode *)malloc(sizeof(TrieNode));

for(count = 0; count < 27; count++) // initial the intern node don'thave children

node->pChildren[count] = NULL;node->NotLeaf = true; //it isn't a leafnode->word[0] = 0; //so we store the null string in node

return node;}

//function performs a search in the TRIE when a string or key is passed.void Find(TrieNode *trie, char keyWord[20]){


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TrieNode *next, *index, *data;int count;

next = trie; //start searching from the trie root

if(next == NULL) //trie is empty{

cout pChildren[keyWord[count]-'a'] != NULL))

{// .... go down with 1 levelnext = index->pChildren[keyWord[count]-'a']; // the actual node

goes down with 1 level in trie following the pChildren field // corresponding t

o the actual letter from keyWordindex = next;count ++ ; //move right in word with 1 level (1 letter)

}

if(next == NULL)cout word,keyWord))cout


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re the new wordtrie->pChildren[keyWord[0]-'a'] = new_leaf; //add the leaf into

the trie in the corresponding position

return trie;}else // non empty trie ..start searching

index = next;

inWordIndex = 0; //move down in trie while end of word isn't reached and the pChildren branch node doesn't leads to NULL

while((inWordIndex < lenght) &&(index->NotLeaf == true)&&(index->pChildren[keyWord[inWordIndex]-'a'] != NULL))

{ // .... go down with 1 levelparent = next; //set as parent the actual nodenext = index->pChildren[keyWord[inWordIndex]-'a']; // the actu

al node goes down with 1 level in trie following the pChildren field // correspo

nding to the actual letter from keyWordindex = next;

inWordIndex++; //move right in word with 1 level (1 letter)}

// if pChildren branch node points to NULL(end of prefix is reached) andno word already inserted, simply insert the word

if((inWordIndex < lenght) && (index->pChildren[keyWord[inWordIndex]-'a']== NULL) && (index->NotLeaf == true))

{new_index = NewLeaf(keyWord);index->pChildren[keyWord[inWordIndex]-'a'] = new_index;

return trie;}else

data=next;

if(!strcmp(data->word,keyWord))cout word[0] != '\0') if(strlen(data->word) < prefixLenght)// determine the minimum

lenght of words prefixLenght = strlen(data->word);

}

bool createIntern = false;// Build a new subtree while the word to be inserted and the item that w

as in the leaf node have the same letters or the end of one of them is reached.while((inWordIndex word[0] != '\0' )&& (data-

>word[inWordIndex-1] == keyWord[inWordIndex-1])) || (data->word[0] == '\0'))){


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intern = NewIntern();//create a new intern nodeparent->pChildren[keyWord[inWordIndex-1]-'a'] = intern; //insert

this node in the corresponding field in parent->pChildren(with respect to the letter index in array)

parent->NotLeaf = true;parent = intern; // move down in tree with 1 levelinWordIndex++; // move right in word with 1 letter

createIntern = true;}if(createIntern) inWordIndex--;

//if items have a common prefixif((inWordIndex != prefixLenght) || ((inWordIndex == prefixLenght)&&(str

len(keyWord) == strlen(data->word)))){//store in leaves the item that was to be inserted and the item that wa

s originally in the leaf node.parent->pChildren[data->word[inWordIndex]-'a'] = oldChildren;parent->pChildren[keyWord[inWordIndex]-'a'] = newWord;

}else // one word (keyWord or an item that was originally in the leaf nod

e) represents a prefix for the other(s) item(s)if(data->word[0] != '\0')//just a word that has as prefix the ke

yword or vice versa // insert the items as information nodes corresponding to the pChildren fields of prefixLenght and blank character

if(strlen(data->word) pChildren[26] = oldChildren;parent->pChildren[keyWord[prefixLenght]-'a'] = newWord;

}else{

parent->pChildren[26] = newWord;parent->pChildren[data->word[prefixLenght]-'a'] = oldChi

ldren;

}else// Two or more words that have the same prefix{

for (int count = 0 ; count < 27;count++)//copy the subtree

parent->pChildren[count] = oldChildren->pChildren[count];

parent->pChildren[26] = newWord;//newWord is the prefix(save in blank pointer)

}

return trie;}

//function for displaying the words stored in the trievoid DisplayTrie(TrieNode *trie, int nivel){

int count;

if(trie){

if (trie->NotLeaf != true) // if TrieNode is a leaf(a word is stored in)


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{ // display the string at his levelfor (count = 0; count NotLeaf != true && strncmp( str ,trie -> word,strlen(str) )== 0 ) // if TrieNode is a leaf(a word is stored in)

{

cout word = 0; count--) Complete(trie->pChildren[count], str);

}

}

int main(){

TrieNode *trie;char UserInputWord[20], cont_insert=' ';int option = 0; //stores the user's input(the chosen option)

char str[20] ;

trie = NULL;

label_menu:while( option != 5){

//display menucout


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cout UserInputWord;

trie = Insert(trie,UserInputWord);

cout

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