國立暨南國際大學 99 學年度第二學期小考試卷

(考試時間: 16:30-16:45)

1. (10%) Determine whether the following code has syntax erros or not.  If it is correct, predict its output.  If it is
   incorrect, point out the mistake(s).
   
   #include <iostream>
   using std::cout;
   using std::endl;
   
   class CBox                             // Base class
   {
     public:
       // Function to show the volume of an object
       void ShowVolume() const
       {
         cout << endl
              << "CBox usable volume is " << Volume(); 
       }
   
       // Function to calculate the volume of a CBox object
       virtual double Volume() const
       { return m_Length*m_Width*m_Height; }
   
       // Constructor
       CBox(double lv = 1.0, double wv = 1.0, double hv = 1.0)
                               :m_Length(lv), m_Width(wv), m_Height(hv) {}
   
     protected:
       double m_Length;
       double m_Width;
       double m_Height;
   };
   
   class CGlassBox: public CBox           // Derived with protected specifier
   {
     public:
       // Function to calculate volume of a CGlassBox
       // allowing 15% for packing
       virtual double Volume() const
       { return 0.5*m_Length*m_Width*m_Height; }
   
       // Constructor
       CGlassBox(double lv, double wv, double hv): CBox(lv, wv, hv){}
   };
   
   int main()
   {
     CBox myBox(2.0, 3.0);            // Declare a base box
     CGlassBox myGlassBox(2.0, 3.0, 4.0);  // Declare derived box of same size
     CBox* pBox(nullptr);       // Declare a pointer to base class objects
   
     pBox = &myBox;             // Set pointer to address of base object
     pBox->ShowVolume();        // Display volume of base box
     pBox = &myGlassBox;        // Set pointer to derived class object
     pBox->ShowVolume();        // Display volume of derived box
   
     cout << endl;
     return 0;
   }
   
   
   

2. (10%) Determine whether the following code has syntax erros or not.  If it is correct, predict its output.  If it is
   incorrect, point out the mistake(s).
   
   #include <iostream>
   using std::cout;
   using std::endl;
   struct S {
      int i;   // size 4
      char j;   // size 1
      double k;   // size 8
   };
   struct T {
      int i;  // size 4
      double k;  // size 8
      char j;  // size 1
   };
   int main() {
      cout << "size of S = " << sizeof(S) << endl;
      cout << "size of T = " << sizeof(T) << endl;
     
   }