类继承和使用指针

#include <memory>

class MyClass {
public:
    MyClass() { /* ... */ }
    ~MyClass() { /* ... */ }
};

void example() {
    std::unique_ptr<MyClass> ptr(new MyClass());
    // 不需要手动delete，ptr离开作用域时会自动释放内存
}

void example() {
    MyClass* ptr = new MyClass();
    delete ptr;
    ptr = nullptr; // 防止悬挂指针
}

class Base1 {
public:
    void foo() { /* ... */ }
};

class Base2 {
public:
    void foo() { /* ... */ }
};

class Derived : public Base1, public Base2 {
public:
    void callFooFromBase1() {
        Base1::foo();
    }
    void callFooFromBase2() {
        Base2::foo();
    }
};

#include <iostream>

class Animal {
public:
    virtual void speak() {
        std::cout << "Animal speaks!" << std::endl;
    }
};

class Dog : public Animal {
public:
    void speak() override {
        std::cout << "Dog barks!" << std::endl;
    }
};

int main() {
    Animal* animalPtr = new Dog(); // 使用指针指向派生类对象
    animalPtr->speak(); // 多态调用
    delete animalPtr; // 释放内存
    return 0;
}