学步园

/*************************************************************************
                      用递归的方法进行二叉树的搜索和插入
      当然二叉树的搜索和插入可以不用递归的方法，而且一般情况下递归也不是一
个很好的解决问题的方案，以下函数用一种严谨实现方法仅体现一种考虑问题的思想，
锻炼人严谨的思维方式。
                                                                             Leo,2005/10/6
                                                                      stefzeus@163.com
*************************************************************************/
/*TreeSearch:search for target starting st node root
    pre:    The tree root points has been created.
    post:   The function returns a pointer to a tree node that matches
                target or NULL if the target is not in the tree    */

TreeNode *TreeSearch(TreeNode *root,KeyType target)
{
    if(root)
        {
         if(target < root->entry.key)
            root=TreeSearch(root->left,target);
         else if(target > root->entry.key)
            root=TreeSearch(root->right,target);
        }
    return root;
}

/*InsertTree:insert a new node in the tree
    pre:  The tree root points has been created.The parameter newnode points  to a node that has been created

            and contains a key in its
    post: The node newnode has been inserted into the tree in such a way
             that the properties of a binary search tree are preserved.     */
TreeNode *InsertTree(TreeNode *root,TreeNode *newnode)
{
    if(!root)
        {
         root=newnode;
         root->left=root->right=NULL;
        }
    else if (newnode->entry.key < root->entry.key)
        root->left=InsertTree(root->left,newnode);
    else
        root->right=InsertTree(root->right,newnode);
    return root;
}