1. At present , preorder traversal algorithm is wildly used for OID serializing. However, great maintenance overhead is inevitable when we adopt this algorithm.

2. Enter the tree traversal Preorder traversal of the results and the results of established tree and gives the results after the traversal.

3. At present, preorder traversal algorithm is wildly used for OID serializing.

4. Vessel segments in two images are matched by the preorder traversal of the binary trees, and the method is proved fast and accurate.

5. In the data structure, the binary tree can be uniquely confirmed when the nodes sequences of this binary tree for preorder traversal and inorder traversal are knows.

6. But moving backward is more complicated, because internally the iterator performs a depth-first, preorder traversal of the Rope, visiting each of its leaf nodes.