(1)　　由{4, 9, 0, 1, 8, 6, 3, 5, 2, 7}创建一棵二叉排序树bt并以括号表示法输出；

(2)　　判断bt是否为一棵二叉排序树；

(3)　　采用递归和非递归两种方法查找关键字为6的结点，并输出其查找路径；

(4)　　分别删除bt中的关键字为4和5的结点，并输出删除后的二叉排序树。

-(1) by {4, 9, 0, 1, 8, 6, 3, 5, 2, 7} to create a binary sort tree and bracket notation bt output　(2) to determine whether a two bt Binary sort tree　(3) the use of two methods of recursive and non-recursive lookup keyword node 6, and outputs its search path　(4), respectively, to delete the keyword bt junction 4 and 5, and the output Binary sort tree after deletion.