flowchart TB
    subgraph 继承
        A[Base Class] --> B[Derived A]
        A --> C[Derived B]
        A --> D[Derived C]
    end

    subgraph 修改影响
        CHANGE["修改 Base 的 fly() 方法"]
    end

    CHANGE -.->|影响所有子类!| B
    CHANGE -.->|可能不适用| C
    CHANGE -.->|可能导致 Bug| D

flowchart TB
    subgraph 组合
        CAR[Car] --> E[Engine]
        CAR --> T[Tire 1..4]
        CAR --> GPS[GPS]
    end

    subgraph 更换组件
        E2["V8 Engine"] -.->|替换| E
        T2["Winter Tire"] -.->|替换| T
    end

    note[CAR 不受影响<br/>组件可以独立替换]

classDiagram
    class House {
        +rooms: list[Room]
        +address: str
        +__init__()
    }

    class Room {
        +name: str
        +area: float
        +__init__(name)
    }

    House *-- Room : 组合

    note for House: House 创建 Room
    note for House: House 销毁 → Room 也销毁
    note for Room: Room 不能独立于 House 存在

classDiagram
    class SchoolClass {
        +name: str
        +add_student(Student)
        +add_course(Course)
        +remove_student(Student)
    }

    class Student {
        +name: str
        +student_id: str
    }

    class Course {
        +name: str
        +code: str
    }

    SchoolClass o-- Student : 聚合
    SchoolClass o-- Course : 聚合

    note for SchoolClass: Student 从外部传入
    note for SchoolClass: SchoolClass 销毁 → Student 继续存在

flowchart TB
    subgraph 组合 Composition
        C1[整体] -->|创建| C2[部分]
        C1 -->|拥有| C3[部分]
        C1 -.->|销毁| C4[部分也销毁]
    end

    subgraph 聚合 Aggregation
        A1[整体] -->|引用| A2[部分]
        A1 -->|使用| A3[部分]
        A1 -.->|销毁| A4[部分继续存在]
    end

flowchart LR
    subgraph 紧耦合
        A["class Service:"]
        A1["    logger = FileLogger()"]
        A1 -->|硬编码| AL["只能使用 FileLogger"]
    end

    subgraph 松耦合（DI）
        B["class Service:"]
        B1["    def __init__(self, logger):"]
        B1 -->|注入| BL["可以使用任意 Logger"]
    end

    subgraph 注入方式
        C1["构造器注入<br/>__init__(self, dep)"]
        C2["Setter 注入<br/>set_dep(self, dep)"]
        C3["方法注入<br/>method(self, dep)"]
    end

flowchart TB
    subgraph 继承方案 ❌
        I1[Bird] --> I2[fly]
        I1 --> I3[eat]
        I1 --> I4[sleep]
        I2 -.->|问题| I5[Penguin 不会飞]
    end

    subgraph 组合方案 ✅
        C1["Bird<br/>- fly_behavior<br/>- eat_behavior<br/>- sleep_behavior"]
        C1 -->|调用| C2[FlyBehavior.fly]
        C1 -->|调用| C3[EatBehavior.eat]
        C1 -->|调用| C4[SleepBehavior.sleep]

        C5["Penguin<br/>- walk_behavior<br/>- eat_behavior<br/>- sleep_behavior"]
        C5 -->|调用| C6[WalkBehavior.walk]
    end

classDiagram
    class Car {
        -_engine: Engine
        -_transmission: Transmission
        -_fuel_tank: FuelTank
        -_tires: list[Tire]
        -_gps: GPS
        +start() str
        +drive(km, speed) list
        +stop() str
        +replace_tire(pos, tire) str
        +install_gps(gps) str
    }

    class Engine {
        -_running: bool
        -_rpm: int
        +start() str
        +accelerate(rpm) tuple
        +stop() str
    }

    class Transmission {
        -_gear: str
        +shift(gear) str
        +auto_shift(rpm) str
    }

    class FuelTank {
        -_level: float
        +refill(liters) str
        +consume(liters) bool
    }

    class Tire {
        -_pressure: float
        -_tread_depth: float
        +inflate(psi) str
        +check_tread() str
        +wear(km) void
    }

    class GPS {
        +set_destination(dest) str
        +navigate() str
    }

    Car *-- Engine : 组合
    Car *-- Transmission : 组合
    Car *-- FuelTank : 组合
    Car o-- Tire : 聚合
    Car o-- GPS : 依赖注入