二叉树应用，显示树形结构 对于任意的树型结构按从上到下，从左到右的方式显示出来，要求父结点在子结点的左上方，结点之间不需要连线。-Tree applications, shows that for any tree by the tree structure from top to bottom, left to right show the way, asked the parent node in the upper left sub-node, between nodes do not