要求：1)从终端读入字符集大小为n，及n个字符和n个权值，建立哈夫曼树，进行编码并且输出，并将它存于文件hfmtree中。2)利用已建好的哈夫曼编码文件hfmtree，对存储于文件中的某正文进行编码。输出字符正文，再输出该文的二进制码。3)对2)的编码进行译码，译码结果存储到文件中，并与编码前的文件对比。程序编写

好的，我可以为您提供一个Python的实现。

1. 建立哈夫曼树并输出

import heapq
import pickle

class Node:
    def __init__(self, char=None, weight=0, left=None, right=None):
        self.char = char
        self.weight = weight
        self.left = left
        self.right = right

    def __lt__(self, other):
        return self.weight < other.weight

def build_huffman_tree(chars, weights):
    nodes = [Node(chars[i], weights[i]) for i in range(len(chars))]
    heapq.heapify(nodes)
    while len(nodes) > 1:
        left = heapq.heappop(nodes)
        right = heapq.heappop(nodes)
        parent = Node(weight=left.weight + right.weight, left=left, right=right)
        heapq.heappush(nodes, parent)
    root = nodes[0]
    return root

def encode_huffman_tree(root, code, codes):
    if root.char is not None:
        codes[root.char] = code
        return
    encode_huffman_tree(root.left, code + '0', codes)
    encode_huffman_tree(root.right, code + '1', codes)

# 从终端读入字符集大小为n，及n个字符和n个权值
n = int(input('请输入字符集大小n：'))
chars = []
weights = []
for i in range(n):
    char, weight = input('请输入第{}个字符和权值，用空格分隔：'.format(i + 1)).split()
    chars.append(char)
    weights.append(int(weight))

# 建立哈夫曼树并输出
root = build_huffman_tree(chars, weights)
codes = {}
encode_huffman_tree(root, '', codes)
with open('hfmtree', 'wb') as f:
    pickle.dump((chars, weights, codes), f)
print('哈夫曼编码已经存储到文件hfmtree中')

2. 利用已建好的哈夫曼编码文件对文本进行编码

# 读入文本
with open('text', 'r') as f:
    text = f.read()

# 读入哈夫曼树并建立哈希表
with open('hfmtree', 'rb') as f:
    chars, weights, codes = pickle.load(f)

# 对文本进行编码
encoded_text = ''.join(codes[char] for char in text)

# 输出字符正文和二进制码
print('原始文本：', text)
print('编码后文本：', encoded_text)
print('二进制码：', ''.join(format(ord(c), '08b') for c in encoded_text))

# 存储编码后的文本到文件中
with open('encoded_text', 'w') as f:
    f.write(encoded_text)
print('编码后的文本已经存储到文件encoded_text中')

3. 对编码进行译码并存储到文件中

# 读入编码后的文本
with open('encoded_text', 'r') as f:
    encoded_text = f.read()

# 对编码进行译码
decoded_text = ''
i = 0
while i < len(encoded_text):
    node = root
    while node.char is None:
        bit = encoded_text[i]
        node = node.left if bit == '0' else node.right
        i += 1
    decoded_text += node.char

# 存储译码后的文本到文件中
with open('decoded_text', 'w') as f:
    f.write(decoded_text)
print('译码后的文本已经存储到文件decoded_text中')

# 检验译码的正确性
with open('text', 'r') as f:
    original_text = f.read()
assert decoded_text == original_text, '译码结果与原始文本不一致'
print('译码正确')

希望这个Python程序能够帮助您理解哈夫曼编译码系统的实现过程。