國立暨南國際大學 97 學年度第二學期小考試卷

(考試時間: 14:10-14:40)

1. (10%) Point out the syntax error in the following code.

   // Variation of Ex9_05.cpp
   
   #include <iostream>                    // For stream I/O
   #include <cstring>                     // For strlen() and strcpy()
   using std::cout;
   using std::endl;
   
   class CBox                   // Base class definition
   {
     public:
       // Base class constructor
       CBox(double lv = 1.0, double wv = 1.0, double hv = 1.0):
                            m_Length(lv), m_Width(wv), m_Height(hv)
       {  cout << endl << "CBox constructor called";  }
   
       // Copy constructor
       CBox(const CBox& initB)
       {
         cout << endl << "CBox copy constructor called";
         m_Length = initB.m_Length;
         m_Width = initB.m_Width;
         m_Height = initB.m_Height;
       }  
   
     protected:
       double m_Length;
       double m_Width;
       double m_Height;
   };
   
   class CCandyBox: public CBox
   {
     public:
       char* m_Contents;
   
       // Derived class function to calculate volume
       double Volume() const
       { return m_Length*m_Width*m_Height; }
   
       // Constructor to set dimensions and contents
       // with explicit call of CBox constructor
       CCandyBox(double lv, double wv, double hv, char* str = "Candy")
                                             :CBox(lv, wv, hv)  // Constructor
       {
         cout << endl <<"CCandyBox constructor2 called";
         m_Contents = new char[ strlen(str) + 1 ];
   	        strcpy(m_Contents, str);
       }
   
       // Constructor to set contents
       // calls default CBox constructor automatically
       CCandyBox(char* str = "Candy")               // Constructor
       {
         cout << endl << "CCandyBox constructor1 called";
         m_Contents = new char[ strlen(str) + 1 ];
         strcpy(m_Contents, str);
       }
   
       // Derived class copy constructor
       CCandyBox(const CCandyBox& initCB)
   		: m_Length(initCB.m_Length), m_Width(initCB.m_Width),
   		m_Height(initCB.m_Height)
       { 
         cout << endl << "CCandyBox copy constructor called";
   
         // Get new memory
         m_Contents = new char[ strlen(initCB.m_Contents) + 1 ];
   	  
         // Copy string
         strcpy(m_Contents, initCB.m_Contents);
       } 
   
       ~CCandyBox()                                 // Destructor
       { delete[] m_Contents; }
   };
   
   int main()
   {
     CCandyBox chocBox(2.0, 3.0, 4.0, "Chockies");  // Declare and initialize
     CCandyBox chocolateBox(chocBox);               // Use copy constructor
   
     cout << endl
          << "Volume of chocBox is " << chocBox.Volume()
          << endl
          << "Volume of chocolateBox is " << chocolateBox.Volume()
          << endl;
   
     return 0;
   }
   
   
   
   

2. (10%) Point out the syntax error in the following code.
   
   // Friend functions
   #include <iostream>
   using std::cout;
   
   class CCarton
   {
   public:
   	CCarton(const CBottle& aBottle);
   	double Volume();
   private:
   	double m_Length;						// Carton length
   	double m_Width;							// Carton width
   	double m_Height;						// Carton height
   };
   
   class CBottle
   {   // Let the carton constructor in
   	friend CCarton::CCarton(const CBottle& aBottle);
   public:
   	CBottle(double height, double diameter)
   	{
   		m_Height = height;
   		m_Diameter = diameter;
   	}
   private:
   	double m_Height;		// Bottle height
   	double m_Diameter;		// Bottle diamter
   };
   
   CCarton::CCarton(const CBottle& aBottle)
   	{
   		m_Height = aBottle.m_Height;		// Bottle height
   		m_Length = 4.0*aBottle.m_Diameter;	// Four rows of ...
   		m_Width = 3.0*aBottle.m_Diameter;	// ... three bottles
   	}
   
   double CCarton::Volume()
   	{ return m_Length * m_Width * m_Height;	}
   
   int main()
   {
   	CBottle beer(3.0, 5.0);
   	CCarton aCarton(beer);
   	cout << aCarton.Volume() << "\n";
   }
   
   
   
   
   
   
   

3. (10%) If we replace the OnDraw() function in P.715 as below, please draw a figure to depict what result we shall obtain.
   
   void CSketcherView::OnDraw(CDC* pDC)
   {
       CSketcherDoc* pDoc = GetDocument();
       ASSERT_VALID(pDoc);
       if (!pDoc)
           return;
   
       int x0 = 10;
       int y0 = 210;
       POINT p1, p2;
       for (int i=0; i<=10; i++)
       {
           p1.x = i*20 + x0; p1.y = y0;
           p2.x = x0;        p2.y = y0 - (10-i)*20;
           pDC->MoveTo(p1);
           pDC->LineTo(p2);
       }
   }