C++快速入門---覆蓋方法和過載方法(13)
阿新 • • 發佈:2018-11-04
C++快速入門---覆蓋方法和過載方法(13)
覆蓋方法(overriding)
覆蓋:在基類裡提供一個通用函式,但在它的某個子類裡需要修改這個方法的實現。
子類覆蓋基類的方法。
修改例題,為我們的Animal新增eat()方法,並在Pig和Turtle中覆蓋。
#include <iostream> #include <string> class Animal//基本 { public: Animal(std::string theName); void eat(); void sleep(); void drool();//流口水 protected: std::string name; }; //Pig繼承於Animal class Pig : public Animal { public: Pig(std::string theName); void climb();//上樹 void eat();//new! }; class Turtle : public Animal { public: Turtle(std::string theName); void swim(); void eat(); //new! }; Animal::Animal(std::string theName) { name = theName; } void Animal::eat() { std::cout << "I'm eatting!" << std::endl; } void Animal::sleep() { std::cout << "I'm sleeping!Don't disturb me!" << std::endl; } void Animal::drool() { std::cout << "我是公的,看到母的我會流口水,我正在流口水。。。" << std::endl; } Pig::Pig(std::string theName) : Animal(theName) { } void Pig::climb() { std::cout << "我是一隻漂亮的小母豬豬,我會上樹,我正在爬樹。。噓。。" << std::endl; } void Pig::eat() { Animal::eat(); std::cout << name << "正在吃魚!\n\n"; //new! } Turtle::Turtle(std::string theName) : Animal(theName) { } void Turtle::swim() { std::cout << "我是一隻小甲魚,當母豬想抓我的時候,我就游到海里。。哈哈。。" << std::endl; } void Turtle::eat() { Animal::eat(); std::cout << name << "正在吃東坡肉!\n\n"; //new! } int main() { Pig pig("小豬豬"); Turtle turtle("小甲魚"); //std::cout << "這隻豬的名字是:" << pig.name << std::endl; //錯誤 ///std::cout << "每隻烏龜都有個偉大的名字:" << turtle.name << std::endl; //錯誤 pig.eat(); turtle.eat(); pig.climb(); turtle.swim(); return 0; }
過載方法
過載機制使你可以定義多個同名的方法(函式),只是它們的輸入引數必須不同。(因為編譯器是依靠不同的輸入引數來區分不同的方法)
對eat()方法進行過載:test
#include <iostream> #include <string> class Animal//基本 { public: Animal(std::string theName); void eat(); void eat(int eatCount); void sleep(); void drool();//流口水 protected: std::string name; }; //Pig繼承於Animal class Pig : public Animal { public: Pig(std::string theName); void climb();//上樹 }; class Turtle : public Animal { public: Turtle(std::string theName); void swim(); }; Animal::Animal(std::string theName) { name = theName; } void Animal::eat() { std::cout << "I'm eatting!" << std::endl; } void Animal::eat(int eatCount) { std::cout << "我吃了" << eatCount << "碗餛飩!\n\n"; } void Animal::sleep() { std::cout << "I'm sleeping!Don't disturb me!" << std::endl; } void Animal::drool() { std::cout << "我是公的,看到母的我會流口水,我正在流口水。。。" << std::endl; } Pig::Pig(std::string theName) : Animal(theName) { } void Pig::climb() { std::cout << "我是一隻漂亮的小母豬豬,我會上樹,我正在爬樹。。噓。。" << std::endl; } Turtle::Turtle(std::string theName) : Animal(theName) { } void Turtle::swim() { std::cout << "我是一隻小甲魚,當母豬想抓我的時候,我就游到海里。。哈哈。。" << std::endl; } int main() { Pig pig("小豬豬"); Turtle turtle("小甲魚"); pig.eat(); turtle.eat(); pig.eat(15); pig.climb(); turtle.swim(); return 0; }