有如下程序：
#include　<iostream>
using　namespace　std;
class　Base{
public:
Base(int　x=0){cout<<x;}
};
class　Derived:public　Base{
public:
Derived(int　x=0){cout<<x;}
private:
Base　val;
};
int　main(){
Derived　d(1);
return　0;
}
程序的输出结果是