pset5 unload printed failed to unload but pass valgrind with no leak?

Question

I'm sooo close!! My code is running and printing out misspelled words but stopped at message "could not unload dictionary" (I tried on both large and small). However when I run Valgrind, it's reporting a successful memory freed without any leakage.

Here are the screen shots of Valgrind

below is my codes for unload

// recursive function for freeing children memory

void del_trie(node* ptr)

{

for(int i = 0; i < ALPHABETS; i++)
    if(ptr->children[i] != NULL)
        del_trie(ptr->children[i]);

free(ptr);

return;

}

/** * Unloads dictionary from memory. Returns true if successful else false. */

bool unload(void)

{

node* current = root;

del_trie(current);

if(root != NULL);
    return false;

return true;

}

Can someone Plzzz help?? Thanks beforehand.

Edited code:

// recursive function for freeing children memory

void del_trie(node* ptr)

{

for(int i = 0; i < ALPHABETS; i++)
{
    if(ptr->children[i] != NULL)
        del_trie(ptr->children[i]);

    ptr->children[i] = NULL;
}

ptr = NULL;
free(ptr);
return;

}

/** * Unloads dictionary from memory. Returns true if successful else false. */

bool unload(void)

{

node* current = root;

del_trie(current);

root = NULL;
free(root);

if(root != NULL);
    return false;

return true;

}

Answer 1

When you call free(ptr), it releases the memory pointed to by ptr, but it does not reset the ptr to null. In fact, it doesn't change the contents of the pointer at all. The pointer continues to contain the same address. Thus, your check, if(root != NULL); doesn't work as you expect.

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