國立暨南國際大學 96 學年度第二學期小考試卷

(考試時間: 8:10-8:30)
Open book; turn off computer & mobile phone

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).
   

   #include <iostream>
   using std::cout;
   using std::endl;
   
   class Complex
   {
   	double Re;	// real part
   	double Im;	// imaginary part
   
   public:
   	Complex(double a=0.0, double b=0.0):
   		Re(a), Im(b) { }
   
   	Complex operator* (Complex b)
   	{
   		return Complex(Re*b.Re - Im*b.Im, Re*b.Im + Im*b.Re);
   	}
   
   	void Print(void)
   	{
   		cout << Re;
   		if (Im > 0)
   			cout << "+" << Im << "i";
   		else
   			if (Im<0)
   				cout << Im << "i";
   		cout << endl;
   	}
   };
   
   
   
   void main()
   {
   	Complex a(0.0, 1.0);
   	Complex b(0.0, -1.0);
   	Complex c;
   
   	a.Print();
   	b.Print();
   	c = a * b;
   	c.Print();
   	// Note: "cout << 0.0 << 1.0;" will merely print out "01".
   }
   
   
   
   
   
   
      

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).

   
   #include <iostream>
   
   using std::cout;
   using std::endl;
   
   class Node
   {
   private:
   	int	value;
   	Node*	left;
   	Node*	right;
   
   public:
   	void Inorder(void)
   	{
   		if (this->left)
   			this->left->Inorder();
   		cout << value;
   		if (this->right)
   			this->right->Inorder();
   	}
   	void Preorder(void)
   	{
   		cout << value;
   		if (this->left)
   			this->left->Preorder();
   		if (this->right)
   			this->right->Preorder();
   	}
   	void Postorder(void)
   	{
   		if (this->left)
   			this->left->Postorder();
   		if (this->right)
   			this->right->Postorder();
   		cout << value;
   	}
   
   	Node(int v, Node* L = 0, Node* R = 0)	// Constructor
   		: value(v), left(L), right(R)
   	{	}
   	
   	friend Node* init(void);		// Friend function (P.354)
   };
   
   Node* init(void)
   {
   	Node* three = new Node(3);
   	Node* five = new Node(5);
   	Node* six = new Node(6, five, three);
   	Node* two = new Node(2);
   	Node* seven = new Node(7, two, six);
   	Node* four = new Node(4);
   	Node* nine = new Node(9, four);
   	Node* eight = new Node(8, nine);
   	Node* one = new Node (1, seven, eight);
   	return one;
   }
   
   void main()
   {
       Node* root = init() ;
       root->Inorder();	cout << endl;
       root->Preorder();	cout << endl;
       root->Postorder();	cout << endl;
   }