Polymorphism
Polymorphism is one of the three characteristics of object-oriented C ++
Polymorphic divided into two categories
- Static Polymorphism: function overloading and operator overloading is a static polymorphism, a multiplexing function name
- Dynamic Polymorphism: polymorphism derived class virtual function and operation to achieve
Static polymorphism and dynamic polymorphism differences:
- Static polymorphic function address early binding - compilation phase to determine the function address
- Function address late binding dynamic polymorphism - the operational phase to determine the function address
Here to explain polymorphism through case
class Animal
{
public:
//Speak函数就是虚函数
//函数前面加上virtual关键字，变成虚函数，那么编译器在编译的时候就不能确定函数调用了。
virtual void speak()
{
cout << "动物在说话" << endl;
}
};
class Cat :public Animal
{
public:
void speak()
{
cout << "小猫在说话" << endl;
}
};
class Dog :public Animal
{
public:
void speak()
{
cout << "小狗在说话" << endl;
}
};
//我们希望传入什么对象，那么就调用什么对象的函数
//如果函数地址在编译阶段就能确定，那么静态联编
//如果函数地址在运行阶段才能确定，就是动态联编
void DoSpeak(Animal & animal)
{
animal.speak();
}
//
//多态满足条件：
//1、有继承关系
//2、子类重写父类中的虚函数
//多态使用：
//父类指针或引用指向子类对象
void test01()
{
Cat cat;
DoSpeak(cat);
Dog dog;
DoSpeak(dog);
}
int main() {
test01();
system("pause");
return 0;
}
to sum up:
Polymorphic satisfy the condition
- There inheritance
- Subclasses override the parent class virtual function
Polymorphic Conditions
- Parent pointers or references to sub-class objects
Rewrite: function return value type parameter list exactly the same function name called rewrite
