國立暨南國際大學 100 學年度第一學期小考試卷                   (考試時間: 8:10-8:35)
科目名稱：資訊系統 與網路導論 開課系所：資訊工程 學系 任課教師
 吳坤熹
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 考試日期
 2012.1.6
  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).
    #include <iostream>
    using std::cout;

    int main()
    {
        int i, n = 2012;
        for (i=1; i<7; i++)
        {
            int n = 0;
            for (int j=1; j<=i; j++)
                n += j;        // scope of variable n
            cout << n << "\n";
        }
        cout << n << "\n";
        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).
    // modulus
    #include <iostream>
    using std::cout;
    using std::endl;

    int mod(int a, int b)
    {
          do a -= b;
          while (a >= b);
          return a;
    }

    int main()
    {
          cout << mod(2012, 7) << 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).
    // Caesar Cipher
    #include <iostream>
    using std::cout;
    using std::endl;

    void encrypt(char* a, int key)
    {
       while (*a)
       {
          if (*a >= 'A' && *a <='Z')
              *a = (*a - 'A' + key) % 26 + 'A';
          a++;
       }
    }

    int main()
    {
       char msg[] = "HELLO NCNU";
       encrypt(msg, 3);
       cout << msg << "\n";
           return 0;
    }

  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).
    #include <iostream>
    using std::cout;

    float average(float a, float b);
    float average(float a, float b, float c);       // overloading

    int main()
    {
        cout << average(1.0, 5.2, 7.0) << "\n";
        cout << average(4,0, 5.0) << "\n";
        return 0;
    }

    float average(float a, float b)
    { return (a+b)/2.0; }

    float average(float a, float b, float c)
    { return (a+b+c)/3.0; }

  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).
    6.  // binary tree
    #include <iostream>
    using std::cout;

    struct Node
    {
        char label;
        Node* left;
        Node* right;
    };

    void postorder(Node* p);    

    int main()
    {
        Node First        = { 'A', NULL, NULL };
        Node Second       = { 'B', NULL, NULL };
        Node Third        = { 'C', NULL, NULL };
        Node Fourth       = { 'D', NULL, NULL };
        Node Fifth        = { 'E', &First, &Second };
        Node Sixth        = { 'F', &Third, &Fourth };
        Node Seventh      = { 'G', &Fifth, &Sixth };

        postorder(&Seventh);
        return 0;
    }

    void postorder(Node* p)
    {
        if (p)
        {      
            postorder(p->left);
            postorder(p->right);
            cout << p->label;
        }
    }