子将奚先？

Which would you place first?

《新英汉大辞典》

这两个函数均按照深度优先的顺序遍历树，但两者的差异在于先访问一个节点还是先访问其子节点。

Both functions walk the tree in depth-first order but they differ in whether a node is visited before or after its children.

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在对当前子节点进行任何其它处理之前，先装入下个子节点的引用(第7行)。

The reference for the next child node is loaded (line 7) before any other processing is done for the current child.

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