ezeasasclass Person
{
public:
virtual void fun6()
{
cout << "Person::fun6()" << endl;
}
public:
int _name;
int _major;
};
class Student :virtual public Person
{
public:
virtual void fun1()
{
cout << "Student::fun1()" << endl;
}
virtual void fun2()
{
cout << "Student::fun2()" << endl;
}
public:
int number;
};
class Teacher :virtual public Person
{
public:
virtual void fun3()
{
cout << "Teacher::fun3()" << endl;
}
virtual void fun4()
{
cout << "Teacher::fun4()" << endl;
}
public:
int num;
};
class TeachStudent :public Student,public Teacher
{
public:
virtual void fun4()
{
cout << "TeachStudent::fun4()" << endl;
}
virtual void fun5()
{
cout << "TeachStudent::fun5()" << endl;
}
public:
int id;
};
Student 类和Teacher类都继承了 Person类， 而TeachStudent又继承了这两个类
TeachStudent s1;//定义一个TeachStudent 类S1
打开内存窗口查看s1的地址如下
通过给具体的对象成员赋值可已查看内存中成员的分布
s1._name = 1;//
s1._major = 2;
s1.number = 20;
s1.num = 9;
s1.id = 10;
a's
则类在内存中的分布情况如下图：
则可以画出内存分布图如下:
对其中的指针进行分析。写出代码如下
typedef void (*FUNC) ();
void PrintVtable(int *vTable)
{
cout << "虚表地址" << vTable << endl;
for (int i = 0; vTable[i] != 0; ++i)
{
printf( "第%d个虚函数地址：0x%x，->" , i, vTable[i]);
FUNC f = (FUNC )vTable[i];
f();
}
}
void test()
{
TeachStudent s1;
// Student s2;
///s2._name = 6;
//s2.number = 12;
s1._name = 1;
s1._major = 2;
s1.number = 20;
s1.num = 9;
s1.id = 10;
int *vTable1= (int *)(*(int *)&s1);//
PrintVtable(vTable1);
int *vTable2 = (int *)(*((int *)&s1 + 3));
int *vTable3 = (int *)(*((int *)&s1 + 7));
PrintVtable(vTable2);
PrintVtable(vTable3);
}
对其中的虚表指针进行强制类型转换，输出每个虚表指针中的虚函数如下图：
还有两个指针：在内存中可以看到其值为：
值为 -4 24；
值为-4 12；
分析可得 其中存的为 当前对象到虚表指针的偏其移地址 以及到共有的虚函数的的偏移地址。
所以可得出虚拟继承在内存中存在方式为：
