7[完成题]
 在下面程序横线处填上适当的字句，使其输出结果为0，56，56。

＃include <iostream.h>

class base{

   public:

     

在下面程序横线处填上适当的字句，使其输出结果为0，56，56。

＃include <iostream.h>

class base{

   public:

      _________func( ){return 0;}

};

class derived:public base{

   public:

       int a,b,c;

       _________ setValue(int x,int y,int z){a=x;b=y;c=z;}

       int func( ){return(a b)*c;}

};

void main()

{

  base b;

  derived d;

  cout<<b.func( )<<′,′;

  d.setValue(3,5,7);

  cout<<d.func( )<<′,′;

  base& pb=d;

  cout<<pb.func( )<<end1;

}

func( ){return 0;}

};

class derived:public base{

   public:

       int a,b,c;

       _________ setValue(int x,int y,int z){a=x;b=y;c=z;}

       int func( ){return(a b)*c;}

};

void main()

{

  base b;

  derived d;

  cout<<b.func( )<<′,′;

  d.setValue(3,5,7);

  cout<<d.func( )<<′,′;

  base& pb=d;

  cout<<pb.func( )<<end1;

}