从键盘输入一个数据文件（字符串），储存并统计各字符以及各字符出现的次数，设计并输出每个字符对应的哈夫曼编码。的代码

好的，这里是一个Python实现的代码示例：

import heapq
from collections import defaultdict

# 定义节点类
class Node:
    def __init__(self, char=None, freq=0, left=None, right=None):
        self.char = char    # 节点对应的字符
        self.freq = freq    # 节点对应的出现次数
        self.left = left    # 左子节点
        self.right = right  # 右子节点

    # 定义 __lt__ 方法，用于堆排序
    def __lt__(self, other):
        return self.freq < other.freq

# 统计各字符出现次数
def count_chars(s):
    freq = defaultdict(int)
    for c in s:
        freq[c] += 1
    return freq

# 构建哈夫曼树
def build_huffman_tree(freq):
    heap = []
    for c, f in freq.items():
        node = Node(char=c, freq=f)
        heapq.heappush(heap, node)

    while len(heap) > 1:
        left = heapq.heappop(heap)
        right = heapq.heappop(heap)
        parent = Node(freq=left.freq + right.freq, left=left, right=right)
        heapq.heappush(heap, parent)

    root = heapq.heappop(heap)
    return root

# 生成哈夫曼编码
def generate_huffman_codes(root):
    codes = {}
    def dfs(node, code):
        if node is None:
            return
        if node.char is not None:
            codes[node.char] = code
            return
        dfs(node.left, code + '0')
        dfs(node.right, code + '1')
    dfs(root, '')
    return codes

# 读取数据文件
filename = input("请输入数据文件名：")
with open(filename, 'r') as f:
    s = f.read()

# 统计各字符出现次数
freq = count_chars(s)

# 构建哈夫曼树
root = build_huffman_tree(freq)

# 生成哈夫曼编码
codes = generate_huffman_codes(root)

# 输出每个字符对应的哈夫曼编码
print("字符\t出现次数\t哈夫曼编码")
for c, f in freq.items():
    code = codes[c]
    print(f"{c}\t{f}\t\t{code}")

这段代码首先读取一个数据文件，并使用 `count_chars` 函数统计各字符出现次数。然后，使用 `build_huffman_tree` 函数构建哈夫曼树，并使用 `generate_huffman_codes` 函数生成哈夫曼编码。最后，输出每个字符对应的哈夫曼编码。