实验内容：能够使用创建二叉树，并使用先序、中序、后序、层序的方法遍历二叉树中所有结点，输出二叉树的高度，统计二叉树叶子结点的个数。写代码

实验内容涉及到编程中常见的数据结构——二叉树的操作。首先，你需要了解二叉树的基本构建，通常通过递归或迭代的方式来创建节点。每个节点包含两个指针，指向左孩子和右孩子。

下面是使用Python语言创建基本二叉树并遍历的示例：

class TreeNode:
    def __init__(self, val=0, left=None, right=None):
        self.val = val
        self.left = left
        self.right = right

def create_tree(values):   # 创建二叉树函数，传入一个值列表
    if not values:
        return None
    mid = len(values) // 2
    root = TreeNode(values[mid])
    root.left = create_tree(values[:mid])  # 递归左子树
    root.right = create_tree(values[mid+1:])  # 递归右子树
    return root

# 遍历方法：
def pre_order_traversal(node):
    if node is not None:
        print(node.val)
        pre_order_traversal(node.left)
        pre_order_traversal(node.right)

def in_order_traversal(node):
    if node is not None:
        in_order_traversal(node.left)
        print(node.val)
        in_order_traversal(node.right)

def post_order_traversal(node):
    if node is not None:
        post_order_traversal(node.left)
        post_order_traversal(node.right)
        print(node.val)

def level_order_traversal(node):
    if node is not None:
        queue = [node]
        while queue:
            node = queue.pop(0)
            print(node.val)
            if node.left:
                queue.append(node.left)
            if node.right:
                queue.append(node.right)

# 计算高度和叶节点数：
def height(node):
    if node is None:
        return 0
    else:
        left_height = height(node.left)
        right_height = height(node.right)
        return max(left_height, right_height) + 1

def count_leaves(node):
    if node is None:
        return 0
    elif node.left is None and node.right is None:
        return 1
    else:
        return count_leaves(node.left) + count_leaves(node.right)