WAP to do AutoCorrection of Word Using Trie

/*
ASSUMPTIONS:
All characters are case insensitive
ENHANCEMENTS:
Auto correction of word
Display all words in postorder

SAMPLE DATA: - ALGO, ALL, ALSO, ASSOC, TREE, TRIE

+--> [G] ---+--> [O]
|
+--> [L] ---+--> [L]
| |
+--> [A] ---+ +--> [S] ---+--> [O]
| |
| +--> [S] ---+--> [S] ---+--> [O] ---+--> [C]
[\0] ---+
| +--> [E] ---+--> [E]
| |
+--> [T] ---+--> [R] ---+
|
+--> [I] ---+--> [E]

*/

#include
#include

using namespace std;

class trie
{
private:
struct node
{
char character; // character of the node
bool eow; // indicates a complete word
int prefixes; // indicates how many words have the prefix
node* edge[26]; // references to all possible sons
}*root; // trie root node

void preorder_display(node *); // preorder display
void truncate_node(node *); // Deletes node and sub-nodes
void delete_node(node *); // Deletes node if prefixes is 1

public:
trie(); // constructor
~trie(); // destructor

void insert_word(char *); // to insert a word
void delete_word(char *); // to delete a word
bool search_word(char *); // to search a word

void display(); // display complete trie
};

trie::trie()
{
root = new node();
root->character = '\0';
root->prefixes = 0;
root->eow = false;
for(int i=0;i<26;i++)
{
root->edge[i] = NULL;
}
}

trie::~trie()
{
truncate_node(root);
}

void trie::truncate_node(node* n)
{
for(int i=0;i<26;i++)
{
if(n->edge[i] != NULL)
{
truncate_node(n->edge[i]);
}
}
delete n;
}

void trie::insert_word(char* s)
{
node *t = root;
while(*s != '\0')
{
int c = toupper(*s) - 'A';
if(t->edge[c] == NULL)
{
node* n = new node();
n->character = *s;
n->eow = false;
n->prefixes = 1;
for(int i=0;i<26;i++)
{
n->edge[i] = NULL;
}
t->edge[c] = n;
t = n;
}
else
{
t = t->edge[c];
t->prefixes++;
}
*s++;
}
t->eow = true;
}

bool trie::search_word(char* s)
{
node *t = root;
while(*s != '\0')
{
int c = toupper(*s) - 'A';
if(t->edge[c] == NULL)
{
return false;
}
else
{
t = t->edge[c];
}
*s++;
}
if(t->eow == true)
return true;
else
return false;
}

void trie::delete_word(char* s)
{
node* t = root;
while(*s != '\0')
{
int c = toupper(*s) - 'A';
if(t->edge[c] == NULL)
{
return;
}
else if(t->edge[c]->prefixes == 1)
{
truncate_node(t->edge[c]);
t->edge[c] = NULL;
return;
}
else
{
t = t->edge[c];
}
*s++;
}
}

void trie::display()
{
preorder_display(root);
}

void trie::preorder_display(node* t)
{
if(t == NULL)
return;

cout << "iterating :: " << t->character << " :: " << t->eow << " :: " << t->prefixes << endl;

for(int i=0;i<26;i++)
{
if(t->edge[i] != NULL)
preorder_display(t->edge[i]);
}
}



int main()
{
trie mytrie;
char *s[] = {"tree","trie","algo","assoc","all","also","ass"};
for(int i=0;i {
mytrie.insert_word(s[i]);
}

mytrie.display();

if(mytrie.search_word("all") == true) cout << "all exist" << endl;
else cout << "all do not exist" << endl;

mytrie.delete_word("all");

if(mytrie.search_word("all") == true) cout << "all exist" << endl;
else cout << "all do not exist" << endl;

mytrie.display();
}