國立暨南國際大學 103 學年度第二學期小考試卷

1. (10%) Determine whether the following code is correct or not.  If it is correct, predict its output.  If it is incorrect, point out the mistake(s).
   
   // strlen vs. sizeof
   #include <iostream>
   #include <cstring>
   using std::cout;
   using std::endl;
   
   int main()
   {
       char s[20] = "This War Of Mine";
       cout << strlen(s) << endl;
       cout << sizeof(s) << endl;
       return 0;
   }
   
   
   
2. (10%)Suppose we compile and run the following code on a 64-bit host, where each pointer (memory address) occupies 64 bits, and each character still occupies 8 bits.  Determine whether the following code is correct or not.  If it is correct, predict its output.  If it is incorrect, point out the mistake(s).
   
   // Destructor
   #include <iostream>
   #include <cstring>
   using std::cout;
   using std::endl;
   
   class CMessage
   {
       char* m_pMessage;
   
   public:
       CMessage(const char* text = "Default message")
       {
               m_pMessage = new char[strlen(text) + 1];
               strcpy(m_pMessage, text);
       }
   
       ~CMessage()
       {
               cout << "Destructor called for " << m_pMessage << ".\n";
               delete [] m_pMessage;
       }
   
   };
   
   int main()
   {
       CMessage  game("Real War");
       CMessage movie("Schindler's List");
       cout << sizeof(game) << endl;
       cout << sizeof(movie) << endl;
       return 0;
   }
   
   
3. (10%) Determine whether the following code is correct or not.  If it is correct, predict its output.  If it is incorrect, point out the mistake(s).
   
   // Default Copy Constructor
   #include <iostream>
   using std::cin;
   using std::cout;
   using std::endl;
   
   class CData
   {
       public:
           int  value;
           int* pdata;
   
       CData(int n=0)
       {
           value = n;
           pdata = new(int);
           *pdata = n;
           // cout << "Constructor called with initial value " << n << endl;
       }
   
       void Print()
       {
           cout << value << '\t' << *pdata << endl;
       }
   };
   
   int main()
   {
       CData a(5);
       CData b = a;
   
       b.Print();
       a.value = *a.pdata = 20;
       a.Print(); b.Print();
       return 0;
   }