C++ 接口函数的覆写

//类对象操作的时候内部构造会有一个隐性的this指针
//继承，在新类中添加原来类中没有的操作和数据结构
//c++面向对象的关键是继承和接口
#include <iostream>
using namespace std;
class A
{
protected:
int m_data;
public:
A(int data = 0)
{
m_data = data;
}
int GetData()
{
cout << "A::GetData()" << endl;
return doGetData();
}
virtual int doGetData()
{
cout << "A:: doGetData()" << endl;
return m_data;
}
};
class B :public A
{
protected:
int m_data;
public:
B(int data = 1)
{
m_data = data;
}
int doGetData()
{
cout << "B::doGetData()" << endl;
return m_data;
}
};
class C :public B
{
protected:
int m_data;
public:
C(int data = 2)
{
cout << "C::C(int data = 2)" << endl;
m_data = data;

}
};
int main()
{
C c(10);
cout << c.GetData() << endl;
cout << c.A::GetData() << endl; 
cout << c.B::GetData() << endl;
cout << c.C::GetData() << endl;
cout << c.doGetData() << endl;
cout << c.A::doGetData() << endl;
cout << c.B::doGetData() << endl;
cout << c.C::doGetData() << endl;
return 0;

}

运行结果：