c++继承中的对象模型

我们知道继承方式有三种

public,protect,private

不同继承方式，在子类中有些是不可以访问的

那么我们想知道到底子类继承了多少？

看代码做一下验证

#include<bits/stdc++.h>
using namespace std;

class father
{
public:
    int a;
protected:
    int b;
private:
    int c;
};

class son1:public father
{
public:
    int d;
};

class son2:protected father
{
public:
    int d;
};

class son3:private father
{
public:
    int d;
};
void test()
{
    son1 s1;
    cout << "size of s1 is " << sizeof(s1) << endl;

    son2 s2;
    cout << "size of s2 is " << sizeof(s2) << endl;

    son3 s3;
    cout << "size of s3 is " << sizeof(s3) << endl;
}

int main()
{
    test();
    return 0;
}

无论何种继承都是16,也就是说父类的东西都继承下来了。只是有些访问权限

需要注意，private 继承方式。虽然基类的public 和 protected 成员在子类中都变成了private

但是子类仍然可以访问，而原来的private是不能访问的

#include<bits/stdc++.h>
using namespace std;

class father
{
    public:
        int a = 1;
    protected:
        int b = 2;
    private:
        int c = 3;        
};

class son:private father
{
       public:
           int d = 4;
           void f()
           {
               cout << this->a << endl;
               cout << this->b << endl;
        }
};

void test()
{
    son s1;
    s1.f();
}

int main()
{
    test();
    return 0;
}