下面程序的输出结果是 【15】 。
#include <iostream>
using namespace std;
class base
{
protected:
int a;
public:
base(){cout<<"0":}
};
class basel: virtual public base
{
public:
base1(){ cout<<"1";}
};
class base2 : virtual public base
{
public:
base2(){cout<<"2";}
};
class derived : public base1,public base2
{
public:
derived () {cout<<"3"; }
}
int main ()
{
derived obj;
cout<<end1;
return 0;
}