用python编写：四则运算

以下是一个简单的四则运算程序，可以进行加减乘除：

import random

# 生成随机数
def generate_num(min_num, max_num):
    return random.randint(min_num, max_num)

# 生成随机运算符
def generate_operator():
    operators = ['+', '-', '*', '/']
    return random.choice(operators)

# 计算表达式结果
def calculate(num1, num2, operator):
    if operator == '+':
        return num1 + num2
    elif operator == '-':
        return num1 - num2
    elif operator == '*':
        return num1 * num2
    elif operator == '/':
        if num2 == 0:
            raise ValueError('除数不能为零')
        return num1 / num2

# 生成表达式
def generate_expression(min_num, max_num):
    num1 = generate_num(min_num, max_num)
    num2 = generate_num(min_num, max_num)
    operator = generate_operator()
    expression = '{} {} {}'.format(num1, operator, num2)
    try:
        result = calculate(num1, num2, operator)
    except ValueError as e:
        return generate_expression(min_num, max_num)
    return expression, result

# 主函数，可以生成多个表达式
def main(num_expressions=10, min_num=0, max_num=100):
    for i in range(num_expressions):
        expression, result = generate_expression(min_num, max_num)
        print('{} = {}'.format(expression, result))

if __name__ == '__main__':
    main()

使用示例：

>>> main(num_expressions=5, min_num=1, max_num=10)
6 - 1 = 5
4 * 7 = 28
4 / 2 = 2.0
7 / 2 = 3.5
2 + 10 = 12