c++基本语法---继承修饰符

#include 
using namespace std;

class A{
	public:
	int a ;
	A(){
		a1 = 1;
		a2 = 2;
		a3 = 3;
		a = 4;
	}
	
	void fun(){
		cout << a << endl;
		cout << a1 << endl;
		cout << a2 << endl;
		cout << a3 << endl;
	}
	
	public:
	int a1;
	protected:
	int a2;
	private:
	int a3;
};

class B : private A{
	public:
	int a;
	B(int i){
		A();
		a = i;
	}
	void fun(){
		cout << a << endl;
		cout << a1 << endl;
		cout << a2 << endl;
		//cout << a3 << endl;
	}
};
int main()
{	
	B b(10);
	cout << b.a << endl;
	//cout << b.a1 << endl;
	//cout << b.a2 << endl;
	//cout << b.a3 << endl;
    return 0;
}