Cherno c++ learning -- inheritance and virtual function

最新推荐文章于 2025-04-27 09:27:11 发布

转载最新推荐文章于 2025-04-27 09:27:11 发布 · 295 阅读

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本文深入探讨了C++中的类继承特性，通过具体代码示例解释了子类如何包含父类的所有public和protected属性。同时，文章详细介绍了虚函数的概念，包括Vtable的生成与使用，以及动态调度机制，展示了如何实现多态性和运行时函数覆盖。

Cherno视频：https://www.youtube.com/watch?v=oIV2KchSyGQ&list=PLlrATfBNZ98dudnM48yfGUldqGD0S4FFb&index=28

子类包含了父类所有的public，protected属性：

#include<iostream>

class Entity {
public:
	float X, Y;
	void Move(int ax, int ay) {
		X += ax;
		Y += ay;

	}
};

class Player :Entity
{
public:
	char * name;

	char * GetName()const {
		return name;
	}
};



int main() {
	std::cout << "sizeof(Entity): "<<sizeof(Entity) << std::endl;
	std::cout << "sizeof(Player): "<<sizeof(Player) << std::endl;

	std::cin.get();
}

virtual function

dynamic dispatch --->compile is typically implemented by our V table

a V table is a table which contains a mapping for all the virtual functions inside out base class

so that we can map them to the correct overwritten function at runtime


class Entity {
public:
	virtual std::string GetName() const {//virtual -->tell compiler to  generate a V table for this function
		return "Entity";             //so that if it is overwritten youcan point to the correct function with this table
	}
};

class Player : public Entity
{
public:
	Player(const std::string& name):
		m_name(name){}
	std::string  m_name;

	std::string  GetName()  const override{
		return m_name;
	}
};
void PrintName(Entity* entity) {
	std::cout << entity->GetName() << std::endl;
}
int main() {
	
	Entity* e = new Entity();
	PrintName(e);
	Player* p = new Player("Cherno");
	PrintName(p);

	std::cin.get();
}