多继承体系下构造函数的调用
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| struct Student {
int m_score;
Student(int score) : m_score(score) {}
void study() {
cout << "student:study() score = "<< m_score << endl;
}
};
struct Worker {
int m_salary;
Worker(int salary) : m_salary(salary) {};
void work() {
cout << "worker:: work salary = " << m_salary << endl;
}
};
struct Underground : Student, Worker {
int m_grade;
Underground(int score, int salary, int grade) :m_grade(grade),
Student(score), Worker(salary) {}
void play() {
cout << "Unerground::play grade = " << m_grade << endl;
}
};
|
多继承-虚函数
如果子类继承的多个父类都有虚函数，那么子类对象就会产生对应的多个虚表
菱形继承
菱形继承带来的问题：
最底下子类从基类继承的成员变量冗余、重复
虚继承
虚继承可以解决菱形继承存在的问题
最上层的类是虚基类
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| struct Person {
int m_age;
};
struct Student : virtual Person {
int m_score;
};
struct Worker : virtual Person {
int m_salary;
};
struct Undergraduate : Student, Worker {
int m_grade;
};
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多继承的应用
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| class JobBaomu {
public:
virtual void clean() = 0;
virtual void cook() = 0;
};
class JobTeacher {
public:
virtual void playfootball() = 0;
virtual void playbaseball() = 0;
};
class Student : public JobTeacher, public JobBaomu{
int m_score;
public:
void clean() {
}
void cook() {
}
void playfootball() {
}
void playbaseball() {
}
};
class Worker : JobTeacher{
int m_salary;
void playfootball() {
}
void playbaseball() {
}
};
|
