國立暨南國際大學 98 學年度第二學期小考試卷

(考試時間: 15:30-15:40)

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).
   
   // Using a destructor to free memory
   #include <iostream>          // For stream I/O
   #include <cstring>           // For strlen() and strcpy()
   using std::cout;
   using std::endl;
   
   //Listing 08_01
   class CMessage
   {
     private:
       char* pmessage;                   // Pointer to object text string
   
   
     public:
   
       // Function to display a message
       void Show() const
       {
         cout << endl << pmessage;
       }
   
       // Constructor definition
       CMessage(const char* text = "Default message")
       {
         pmessage = new char[strlen(text) + 1];   // Allocate space for text
         strcpy(pmessage, text);                  // Copy text to new memory
       }
   
       ~CMessage();                               // Destructor prototype
   };
   
   // Listing 08_02
   // Destructor to free memory allocated by new
   CMessage::~CMessage()
   {
     cout << "Destructor called."         // Just to track what happens
          << endl;
     delete[] pmessage;                   // Free memory assigned to pointer
   }
   
   int main()
   {
     // Declare object
     CMessage m("Good morning");
   
     // Dynamic object
     CMessage* pM = new CMessage("Good evening");
   
     m.Show();                // Display 1st message
     pM->Show();              // Display 2nd message
     cout << endl;
   
     // delete pM;              // Manually delete object created with new
      return 0;
   }