BST Deletion, rewrite for "none found"

[stormlifter]

I've got a function here that works perfect for deleting nodes that match a giving string.

My issue is I can't seem to logically find out where to put a statement nor signify that nothing was found... I need some way of letting an outside function know if something was found or not. as I need to do different things if nothing is found.

Thanks

struct Chapter *deletion(struct Chapter* p, char word [])
{
	// Empty Tree case
	if ( p == NULL)
		return p;
	
	// p->word BEFORE word
	else if ( strcmp(p->word,word) > 0 )
		p->left = deletion(p->left, word);
	
	else if ( strcmp(p->word,word) < 0 )
		p->right = deletion(p->right, word);
		
	// found the node to be deleted
	else if (p->left != NULL && p->right != NULL)
	{
	
		//if: more than one of that word exists, don't delete, just decrese count
		if(p->count > 0)
			p->count--;
			
		// else: if only one exists, delete it
		else{	
			// the node has 2 children
			// replace the node with word that is lowest in alphabet in right subtree
			p = smallest(p->right);
			
			// now delete old copy of lowest element
			p->right = deletion(p->right,p->word);
		}
	}
	
	// node has ONE child OR both are NULL
	else
	{
		//if: more than one of that word exists, don't delete, just decrese count
		if(p->count > 0)
			p->count--;
		
		// else: if only one exists, delete it
		else{
			if(p->left != NULL)
				p = p->left;
			else
				p = p->right;
		}
	}
		
	return p;
	
}

[ssharish2005]

i don't really see any where that u are checking your key string with the node data. something like this

if(strcmp(p->data,key) == 0 )

depending on that u delete something in the tree

ssharish2005

[stormlifter]

I have the "greater than" and "less than" statements, the else is "equals", I know for a fact that if it makes it there that a word was found.
My issue is I'm not sure how to tell an outside function that I found a word.

[sl4nted]

if it didn't find anything return null

struct Chapter *temp;

if ((temp = deletion(the_chapter, "word")) == NULL)
    printf("nothing\n");
else
    the_chapter = temp;

somthing along those lines maybe

[jeremy75]

this code is mean

+------+------+------+------+------+------+------+------+
^
p

if p->word is equal with word, p is assinged p->left or p->right

this is not remove p

u must assign
p->left->rigth = p->rigth;
p->rigth->left = p->left;

[stormlifter]

this code is mean

+------+------+------+------+------+------+------+------+
^
p

if p->word is equal with word, p is assinged p->left or p->right

this is not remove p

u must assign
p->left->rigth = p->rigth;
p->rigth->left = p->left;

My deletion code is working as far as I can tell, it deletes the word and counts down the frequency. I'm just trying to find out how to tell the function before it if I deleted something or not.

[stormlifter]

if it didn't find anything return null

struct Chapter *temp;

if ((temp = deletion(the_chapter, "word")) == NULL)
    printf("nothing\n");
else
    the_chapter = temp;

somthing along those lines maybe

I like where this is headed, I'm going to see if I can implement

EDIT: it kind of works, problem is, the return p; actually never ends up returning a null as I run a check on the return and for some reason it never does. I'm looking into this.

[sl4nted]

don't let it get down to the return p;
once you know a word wasn't found do a return NULL;

[stormlifter]

Figured it out, just one darn line that had me.

[vart]

you call strcmp(p->word,word) twice with the same arguments...
The same can be achived calling it once, storing the result value and comparing the result value in your if/else