106 lines
2.9 KiB
Python
106 lines
2.9 KiB
Python
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#!/usr/bin/env python3
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# -*- coding: utf-8 -*-
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"""
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十进制四则运算计算器
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支持加、减、乘、除基本运算
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提供交互式命令行界面
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"""
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def add(a, b):
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"""加法"""
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return a + b
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def subtract(a, b):
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"""减法"""
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return a - b
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def multiply(a, b):
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"""乘法"""
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return a * b
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def divide(a, b):
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"""除法，处理除零错误"""
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if b == 0:
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raise ValueError("除数不能为零")
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return a / b
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def calculate(expression):
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"""
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解析并计算表达式
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表达式格式: 数字1 运算符 数字2，例如: 5 + 3
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支持运算符: +, -, *, /
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"""
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try:
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# 分割表达式
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parts = expression.strip().split()
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if len(parts) != 3:
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raise ValueError("表达式格式错误，请使用格式: 数字 运算符 数字 (例如: 5 + 3)")
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# 解析操作数
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try:
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num1 = float(parts[0])
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num2 = float(parts[2])
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except ValueError:
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raise ValueError("操作数必须是数字")
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# 解析运算符并执行计算
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operator = parts[1]
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if operator == '+':
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result = add(num1, num2)
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elif operator == '-':
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result = subtract(num1, num2)
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elif operator == '*':
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result = multiply(num1, num2)
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elif operator == '/':
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result = divide(num1, num2)
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else:
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raise ValueError(f"不支持的运算符: {operator}，请使用 +, -, *, /")
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return result
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except ValueError as e:
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raise e
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except Exception as e:
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raise RuntimeError(f"计算错误: {e}")
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def main():
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"""主函数，交互式计算器"""
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print("=" * 50)
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print("十进制四则运算计算器")
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print("=" * 50)
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print("使用说明:")
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print(" 1. 输入表达式，格式: 数字 运算符 数字")
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print(" 2. 支持的运算符: + (加), - (减), * (乘), / (除)")
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print(" 3. 示例: 5 + 3, 10.5 * 2, 8 / 4")
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print(" 4. 输入 'exit' 或 'quit' 退出程序")
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print("=" * 50)
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while True:
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try:
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# 获取用户输入
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user_input = input("\n请输入表达式: ").strip()
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# 检查退出命令
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if user_input.lower() in ['exit', 'quit', 'q']:
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print("\n感谢使用计算器，再见！")
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break
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# 跳过空输入
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if not user_input:
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continue
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# 计算并显示结果
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result = calculate(user_input)
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print(f"结果: {result}")
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except ValueError as e:
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print(f"输入错误: {e}")
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except RuntimeError as e:
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print(f"计算错误: {e}")
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except KeyboardInterrupt:
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print("\n\n检测到中断信号，退出程序...")
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break
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except Exception as e:
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print(f"未知错误: {e}")
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if __name__ == "__main__":
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main()
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