4-6.txt

思路很清晰的c++课件。例子很简明

例4.6 保护性成员在私有派生时，为私有的

#include <iostream.h>

class base{			//基类
protected:
	int a;
public:
	void seta(int sa){a=sa;}
};

class derive1:private base{		//私有派生类
protected:
	int b;
public:
	void setb(int sb){b=sb;}
};

class derive2:public derive1{	//公有派生类
  	int c;
public:
	void setc(int sc){c=sc;}
	void show()
	{  cout<<a<<endl;  //Error
           cout<<b<<endl;
	   cout<<c<<endl;
	}
};

void main()
{   base op1;      op1.seta(1);
    derive1 op2;   op2.setb(2);
    derive2 op3;   op3.setc(3);  op3.show();
}