软件构造，生成算式采用CSV、XML、JSON三种形式进行存储并读取。

编写代码完成将生成的算式及习题长期保存下来，采用CSV、XML、JSON三种形式进行存储并读取。提交相关代码及运行截图。

import random
import csv
import json
import xml.etree.ElementTree as ET
from xml.dom import minidom


# 生成随机算式数据
def generate_exercises(count=10):
    exercises = []
    operators = ['+', '-', '*', '/']
    for _ in range(count):
        num1 = random.randint(1, 10)
        num2 = random.randint(1, 10)
        operator = random.choice(operators)

        # 确保不会出现除以零的情况
        if operator == '/' and num2 == 0:
            num2 = 1

        expression = f"{num1} {operator} {num2}"
        result = eval(expression)  # 使用eval计算表达式的结果
        exercises.append({"expression": expression, "result": result})
    return exercises


# CSV 存储与读取
def save_to_csv(data, filename):
    with open(filename, 'w', newline='') as file:
        writer = csv.writer(file)
        writer.writerow(['Expression', 'Result'])
        for item in data:
            writer.writerow([item['expression'], item['result']])


def load_from_csv(filename):
    with open(filename, 'r') as file:
        reader = csv.DictReader(file)
        return [row for row in reader]


# JSON 存储与读取
def save_to_json(data, filename):
    with open(filename, 'w') as file:
        json.dump(data, file, indent=4)


def load_from_json(filename):
    with open(filename, 'r') as file:
        return json.load(file)


# XML 存储与读取
def save_to_xml(data, filename):
    root = ET.Element("Exercises")
    for item in data:
        exercise = ET.SubElement(root, "Exercise")
        ET.SubElement(exercise, "Expression").text = str(item['expression'])
        ET.SubElement(exercise, "Result").text = str(item['result'])

    tree = ET.ElementTree(root)
    xmlstr = minidom.parseString(ET.tostring(root)).toprettyxml(indent="   ")
    with open(filename, 'w') as f:
        f.write(xmlstr)


def load_from_xml(filename):
    tree = ET.parse(filename)
    root = tree.getroot()
    exercises = []
    for exercise in root.findall('Exercise'):
        expression = exercise.find('Expression').text
        result = float(exercise.find('Result').text)  # 假设结果都是数字
        exercises.append({"expression": expression, "result": result})
    return exercises


# 主程序
def main():
    print("请选择操作：")
    print("1. 生成新的算式并保存")
    print("2. 从文件加载算式")
    choice = input("请输入选项 (1 或 2): ")

    if choice == '1':
        count = int(input("请输入要生成的算式数量: "))
        exercises = generate_exercises(count)
        format_choice = input("请选择保存格式 (csv, json, xml): ").strip().lower()
        if format_choice == 'csv':
            save_to_csv(exercises, 'exercises.csv')
            print("算式已保存到 exercises.csv 文件中.")
        elif format_choice == 'json':
            save_to_json(exercises, 'exercises.json')
            print("算式已保存到 exercises.json 文件中.")
        elif format_choice == 'xml':
            save_to_xml(exercises, 'exercises.xml')
            print("算式已保存到 exercises.xml 文件中.")
        else:
            print("未知的文件格式，请输入 csv, json 或 xml.")
    elif choice == '2':
        format_choice = input("请选择加载的文件格式 (csv, json, xml): ").strip().lower()
        if format_choice == 'csv':
            loaded_data = load_from_csv('exercises.csv')
        elif format_choice == 'json':
            loaded_data = load_from_json('exercises.json')
        elif format_choice == 'xml':
            loaded_data = load_from_xml('exercises.xml')
        else:
            print("未知的文件格式，请输入 csv, json 或 xml.")
            return
        print(f"从 {format_choice} 文件加载的数据:")
        print(loaded_data)
    else:
        print("无效的选择，请输入 1 或 2.")


if __name__ == "__main__":
    main()