多重继承的构造顺序

#include<iostream>
using namespace std;

class a{
	public:
		a()
		{
			cout<<"\na\n";
		}
};

class b{
	public:
		b()
		{
			cout<<"\nb\n";
		}
};

class c{
	public:
		c()
		{
			cout<<"\nc\n";
		}
};

class d{
	public:
		d()
		{
			cout<<"\nd\n";
		}
};

class dd{
	public:
		dd()
		{
			cout<<"\ndd\n";
		}
};

class ff{
	public:
		ff()
		{
			cout<<"\nff\n";
		}
};

class dyh:public a,virtual public b,public c,virtual public d
{
	public:
		dyh()	//:a(),b(),c(),d(),s(),ss()
		{
			cout<<"\n类的继承顺序\n";
		}
	protected:
		dd s;
		ff ss;		
};

int main()
{
	dyh aa;
	cout<<"\nok\n";
}