C/C++中虚基类详解及其作用介绍

目录

• 概述
• 多重继承的问题
• 虚基类

• 初始化
• 例子

class N {
public:
    int a;
    void display(){
        cout << "A::a=" << a <<endl;
    }
};

class A : public N {
public:
    int a1;
};

class B : public N {
public:
    int a2;
};

class C: public A, public B{
public:
    int a3;
    void display() {cout << "a3=" << a3 << endl;};
};

int main() {
    C c1;
    // 合法访问
    c1.A::a = 3;
    c1.A::display();
    return 0;
}

class 派生类名: virtual 继承方式 基类名

class N {
public:
    int n;
    N(int n) : n(n) {};
};

class A : virtual public N {
public:
    A(int n) : N(n) {};
};

class B : virtual public N {
public:
    B(int n) : N(n) {};
};

class C: public A, public B{
public:
    C(int n) : N(n), A(n), B(n){};
};

#ifndef PROJECT5_PERSON_H
#define PROJECT5_PERSON_H
#include <iostream>
#include <string>
using namespace std;
class Person {
protected:
    string name;
    char gender;
public:
    Person(string n, char g) : name(n), gender(g) {}
    void display() {
        cout << "name: " << name << endl;
        cout << "gender: " << gender << endl;
    }
};
#endif //PROJECT5_PERSON_H

#ifndef PROJECT5_STUDENT_H
#define PROJECT5_STUDENT_H
#include <string>
#include "Person.h"
using namespace std;
class Student : virtual public Person {
protected:
    double score;
public:
    Student(string n, char g, double s) : Person(n, g), score(s) {};
};
#endif //PROJECT5_STUDENT_H

#ifndef PROJECT5_TEACHER_H
#define PROJECT5_TEACHER_H
#include <string>
#include "Person.h"
using namespace std;
class Teacher : virtual public Person {
protected:
    string title;
public:
    Teacher(string n, char g, string t) : Person(n, g), title(t) {};
};
#endif //PROJECT5_TEACHER_H

#ifndef PROJECT5_GRADUATE_H
#define PROJECT5_GRADUATE_H
#include "Teacher.h"
#include "Student.h"
#include <string>
using namespace std;
class Graduate : public Teacher, public Student{
private:
    double wage;
public:
    Graduate(string n, char g, double s, string t, double w) : Person(n, g), Student(n, g, s), Teacher(n, g, t), wage(w) {};
    void display() {
        Person::display();
        cout << "score: " << score << endl;
        cout << "title: " << title << endl;
        cout << "wages: " << wage << endl;
    };
};
#endif //PROJECT5_GRADUATE_H

#include <iostream>
#include "Graduate.h"
using namespace std;
int main() {
    Graduate grad1("小白",'f',89.5,"教授",1234.5);
    grad1.display();
    return 0;
}