國立暨南國際大學 107 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).
   /* Destructor */
   #include <iostream>
   #include <string>
   using std::cout;
   using std::string;
   
   class Object
   {
   public:
       Object(string s): name(s)
       { cout << name << "\tconstructed.\n"; }
       ~Object()
       { cout << name << "\tdestroyed.\n"; }
   private:
       string name;
   };
   
   void f(string s)
   { Object a(s); }
   
   int main()
   {
       Object a("Alpha");
       f("Foxtro");
       Object b("Bravo");
       return 0;
   }
   
   
2. (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).
   /* cascaded function calls (P.468) */
   #include <iostream>
   
   class Rational
   {
   public:
       Rational(int n, int d): numerator(n), denominator(d) {};
       Rational setNumerator(int i) { numerator = i; return *this; }
       Rational setDenominator(int i) { denominator = i; return *this; }
       void print() { std::cout << numerator << '/' << denominator << std::endl; }
       int numerator;
       int denominator;
   };
   
   int main()
   {
       Rational a(5, 3);
       a.print();
       a.setNumerator(4).setDenominator(9);
       a.print();
       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).
   /* const member function */
   #include <iostream>
   #include <string>
   using std::cout;
   using std::string;
   using std::endl;
   
   class Object
   {
   public:
       Object(string s): name(s) {}
       const print() { cout << "const " << name << endl; }
   private:
       string name;
   };
   
   int main()
   {
       const Object a("Alpha");
       a.print();
       return 0;
   }