Why not use the root of the trie?-CodePudding

I'm trying to understand this program, why do they have to make Trie* pCrawl = root, why don't they just use the root of the tree and insert directly to it:

void insert(struct TrieNode *root, string key)
{
    struct TrieNode *pCrawl = root;
  
    for (int i = 0; i < key.length(); i  )
    {
        int index = key[i] - 'a';
        if (!pCrawl->children[index])
            pCrawl->children[index] = getNode();
  
        pCrawl = pCrawl->children[index];
    }
  
    // mark last node as leaf
    pCrawl->isEndOfWord = true;
}

CodePudding user response：

I don't think pCrawl is needed.

The argument root is a copy of what is passed and modifying that won't affect the caller, so it is free to modify the value of root in the function.

It may be for clarity gained by using clear names for the argument (for input) and variable (for processing).