面向过程->面向对象
？如何实现简单的计算器功能
如计算俩个数字的和差之类，我们需要数字numbe_a、数字number_b、运算符operator以及结果result
面向过程
class Operation: number_a = input("请输入第一个数字:") number_b = input("请输入第二个数字:") operator = input("请输入+ - * /的运算符:") result = 0 if operator == "+": result = number_a + number_b elif operator == "-": result = number_a - number_b elif operator == "*": result = number_a * number_b elif operator == "/" and number_b != 0: result = number_a / number_b print("最终结果：" + result) |
上述代码存在一下几个问题：
1、输入的number_a和number_b是str类型，需要给他们转换为number
2、输入的运算符有可能不在我们的需要范围内，这时候代码没有做校验
3、输入的number_a和number_b如果不可以转换为number类型该怎么处理？
4、逻辑层和业务层在同一个class中，耦合度较高
一般来说一个系统会有逻辑层和业务层，那么我们可以根据这个方面进行拆分
逻辑层
class Operation: def __init__(self, number_a, number_b, operator): self.number_a = float(number_a) self.number_b = float(number_b) self.operator = operator def operation(self): result = 0 if self.operator == "+": result = self.number_a + self.number_b elif self.operator == "-": result = self.number_a - self.number_b elif self.operator == "*": result = self.number_a * self.number_b elif self.operator == "/" and self.number_b != 0: result = self.number_a / self.number_b else: print('存在输入错误！') return "最终结果：" + str(result) |
业务层
if __name__ == '__main__': try: your_number_a = input("请输入第一个数字:") your_number_b = input("请输入第二个数字:") your_operator = input("请输入+ - * /的运算符:") print(Operation(your_number_a, your_number_b, your_operator).operation()) except Exception as e: print('存在输入错误！' + e) |