Python でのオブジェクト指向プログラミングの一般的な問題と解決策

class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age

    def introduce(self):
        print(f"Hi, my name is {self.name} and I am {self.age} years old.")

person1 = Person("Alice", 25)
person1.introduce()  # 输出：Hi, my name is Alice and I am 25 years old.

person2 = Person("Bob", 30)
person2.introduce()  # 输出：Hi, my name is Bob and I am 30 years old.

print(person1.name)  # 输出：Alice
person2.introduce()  # 输出：Hi, my name is Bob and I am 30 years old.

class Student(Person):
    def __init__(self, name, age, grade):
        super().__init__(name, age)
        self.grade = grade

    def introduce(self):
        super().introduce()
        print(f"I am in grade {self.grade}.")

student1 = Student("Tom", 15, 9)
student1.introduce()  # 输出：Hi, my name is Tom and I am 15 years old. I am in grade 9.

class Employee(Person):
    def __init__(self, name, age, job_title):
        super().__init__(name, age)
        self.job_title = job_title

    def introduce(self):
        print(f"Hi, my name is {self.name}. I am a {self.job_title}.")

employee1 = Employee("John", 40, "manager")
employee1.introduce()  # 输出：Hi, my name is John. I am a manager.

class Circle:
    pi = 3.14

    def __init__(self, radius):
        self.radius = radius

    def calculate_area(self):
        return Circle.pi * self.radius * self.radius

circle1 = Circle(5)
print(circle1.calculate_area())  # 输出：78.5
print(Circle.pi)  # 输出：3.14

class MathUtils:
    @staticmethod
    def add(a, b):
        return a + b

    @classmethod
    def multiply(cls, a, b):
        return a * b

print(MathUtils.add(2, 3))  # 输出：5
print(MathUtils.multiply(2, 3))  # 输出：6