Using a double pointer instead of a single pointer

Question

I am working on a binary search tree.

So here is the structure used to represent node:

typedef struct TreeNode
{
int num;
struct TreeNode *left,*right;
}TREENODE;

To insert a node into a tree, I have the following signatire method

void InsertNode(TREENODE **root,int data);

In the above method, why do we need a double pointer. We can use one pointer!

Do we use double pointer to avoid duplication?

+5

Anirudha Feb 21 '12 at 16:27

5 answers

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+2

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+2

Jerry Coffin 21 . '12 16:33

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0

asaelr 21 . '12 16:30

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0

Andrey · Accepted Answer · 2012-02-21T16:29:58+0000

No, this is necessary in case of rebalancing. After changing the balance, you can change the root.

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