Final Exam
C++ Programming
NCNU CSIE

Date: June 22nd, 2012
Time: 08:30-09:30
Open book; turn off computer & mobile phone

1. (10%) Determine whether the following code has syntax errors or not.  If it is correct, predict its output.  If it is incorrect, point out the mistake(s).
   
   // Define a class
   #include <iostream>
   using std::cout;
   using std::endl;
   
   class CBox                     // Class definition at global scope
   {
       double m_Length;           // Length of a box in inches
       double m_Width;            // Width  of a box in inches
       double m_Height;           // Height of a box in inches
   };
   
   int main()
   {
     CBox box1;                   // Declare box1 of type CBox
   
     box1.m_Height = 3.0;         // Define the values
     box1.m_Length = 7.0;         // of the members of
     box1.m_Width  = 2.0;         // the object box1 
   
     cout << "Volume of box1 = "
          <<  box1.m_Height * box1.m_Length * box1.m_Width
          << endl;
     return 0;
   }
   
   
   
2. (10%) Determine whether the following code has syntax errors or not.  If it is correct, predict its output.  If it is incorrect, point out the mistake(s).
   

   // Copy Constructor
   #include <iostream>
   using std::cout;
   using std::endl;
   
   class CBox             // Class definition at global scope
   {
     public:
       // Constructor definition
       explicit CBox(double lv, double bv = 2.0, double hv = 3.0)
       {     
         m_Length = lv;           // Set values of
         m_Width = bv;            // data members
         m_Height = hv;
       }
   
       CBox(CBox& initB)
       {
           m_Length = initB.m_Length;
           m_Width = initB.m_Width;
           m_Height = initB.m_Height;
       }
   
     private: // What would happen if data members are private?
       double m_Length;           // Length of a box in inches
       double m_Width;            // Width  of a box in inches
       double m_Height;           // Height of a box in inches
   };
   
   int main()
   {
     CBox box1(5.0);   
     CBox box2(box1);
     CBox box3 = box2;  
     cout << box3.Volume() << endl;
     return 0;
   }
   
   

   
   
3. (10%) Determine whether the following code has syntax errors or not.  If it is correct, predict its output.  If it is incorrect, point out the mistake(s).

   // Virtual Function
   #include <iostream>
   using std::cout;
   using std::endl;
   
   class Window // Base class  
   {
   public:
   	void Create() 
   	{ cout <<"Base class Window" << endl; }
   };
   
   class CommandButton : public Window
   {
   public:
       virtual void Create()	// "Try to Override a C++ function"
       { cout<<"Derived class Command Button" << endl;	}
   };
   
   int main()
   {
       Window  *x, *y;
     
       x = new Window();
       x->Create();
   
       y = new CommandButton();
       y->Create();
   }
   
   

4. (10%) Determine whether the following code has syntax errors or not.  If it is correct, predict its output.  If it is incorrect, point out the mistake(s).

   // Destructor
   #include <iostream>
   using std::cout;
   using std::endl;
   
   class CBox             // Class definition at global scope
   {
     public:
       // Constructor definition
       explicit CBox(double lv, double bv = 2.0, double hv = 3.0)
       {     
         m_Length = lv;           // Set values of
         m_Width = bv;            // data members
         m_Height = hv;
       }
   
       CBox(CBox& initB)
       {
           m_Length = initB.m_Length;
           m_Width = initB.m_Width;
           m_Height = initB.m_Height;
       }
   
       ~CBox()
       {
           cout << "Destroy a " << m_Length << " x "
                << m_Width << " x " << m_Height << " box.\n";
       }
     
       double m_Length;           // Length of a box in inches
       double m_Width;            // Width  of a box in inches
       double m_Height;           // Height of a box in inches
   };
   
   int main()
   {
     CBox box1(5.0);   
     CBox box2(1.0, 2.0);
     CBox box3 = box2;  
     box3.m_Length = 3.0;  
     return 0;
   }

5. (10%) Determine whether the following code has syntax errors or not.  If it is correct, predict its output.  If it is incorrect, point out the mistake(s).
   
   // Using a static member of a class
   #include <iostream>
   using std::cout;
   
   class CBox
   {
   private:
       static int count;
       static void ShowIt() { cout << count << '\n'; }
       // Can it be a private member function?
   public:
       CBox()  { ++count; }
       ~CBox() { --count; }
   };
   
   int CBox::count = 0;
   
   int main()
   {
       CBox cigar[2];
       cigar[0].ShowIt();
       CBox candybox;
       CBox::ShowIt();
       return 0;
   }
   
   
   
6. (10%) Determine whether the following code has syntax errors or not.  If it is correct, predict its output.  If it is incorrect, point out the mistake(s).
   
   // Overloaded assignment operator for CBox objects
   #include <iostream>
   using std::cout;
   
   class CBox
   {
       private:
           int weight;
       public:
           void ShowWeight() const
           { cout << weight << "\n"; }
   
           CBox(const int w = 0)   // Constructor definition
           { weight = w; }
   
           CBox operator=(const CBox& aBox)
           {
               if (this == &aBox)  // Check adresses, if equal
                   return *this;   // return the 1st operand
   
               // Copy 2nd operand to 1st
               weight = aBox.weight;
   
               return *this;
           }
   };
   
   int main()
   {
       CBox box1(10);
       CBox box2;
       CBox box3(box1);
       (box3 = box2) = box1;
       box3.ShowWeight();
       box3 = box2 = box1;
       box3.ShowWeight();
       return 0;
   }