C++快速入门---多继承(20)
只要你遇到的问题无法只用一个“是一个”关系来描述的时候,就是多继承出场的时候。
例子:
有一部分学生还教课挣钱(助教),这样就存在了即是老师又是学生的复杂关系,也就是同时存在着两个“是一个”关系。
我们需要写一个TeachingStudent类让它同时继承Teacher类和Student类,换句话说,就是需要使用多继承。
基本语法:
class TeachingStudent : public Student, public Teacher
{...}
代码如下:
#include <iostream>
#include <string>
class Person
{
public:
Person(std::string theName);
void introduce();
protected:
std::string name;
};
class Teacher : public Person
{
public:
Teacher(std::string theName, std::string theClass);
void teach();
void introduce();
protected:
std::string classes;
};
class Student : public Person
{
public:
Student(std::string theName, std::string theClass);
void attendClass();
void introduce();
protected:
std::string classes;
};
//助教
class TeachingStudent : public Student, public Teacher
{
public:
TeachingStudent(std::string theName, std::string classTeaching, std::string classAttending);
void introduce();
};
Person::Person(std::string theName)
{
name = theName;
}
void Person::introduce()
{
std::cout << "大家好,我是" << name << ".\n\n";
}
Teacher::Teacher(std::string theName, std::string theClass) : Person(theName)
{
classes = theClass;
}
void Teacher::teach()
{
std::cout << name << "教" << classes << ".\n\n";
}
void Teacher::introduce()
{
std::cout << "大家好,我是" << name << ",我教" << classes << ".\n\n";
}
Student::Student(std::string theName, std::string theClass) : Person(theName)
{
classes = theClass;
}
void Student::attendClass()
{
std::cout << name << "加入" << classes << "学习.\n\n";
}
void Student::introduce()
{
std::cout << "大家好,我是" << name << ",我在" << classes << "学习.\n\n";
}
TeachingStudent::TeachingStudent(std::string theName,
std::string classTeaching,
std::string classAttending)
: Teacher(theName, classTeaching), Student(theName, classAttending)
{
}
void TeachingStudent::introduce()
{
std::cout << "大家好,我是" << Student::name << ".我教" << Teacher::classes << ",";
}
int main()
{
Teacher teacher("小甲鱼", "C++入门班");
Student student("迷途羔羊", "C++入门班");
TeachingStudent teachingStudent("丁丁", "C++入门班", "C++进阶版");
teacher.introduce();
teacher.teach();
student.introduce();
student.attendClass();
teachingStudent.introduce();
teachingStudent.teach();
teachingStudent.attendClass();
return 0;
}