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1. (5%) 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).
   // operator association (P.210)
   #include <iostream>
   
   int main()
   {
       if ( 2 * 6 == 3 * 4 == 12 )
           std::cout << "True" << std::endl;
       else
           std::cout << "False" << std::endl;
       return 0;
   }
   
   
2. (5%) 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).
   
   // comma operator
   #include <iostream>
   using std::cout;
   using std::endl;
   
   int main()
   {
       int i = 4, j = 17;
       cout << (1, 2, 3) + (4, 5, 6) << endl;
       cout << (i=0, i<10, ++i) + (j=100, j>0, --j) << endl;
       return 0;
   }
   
   
3. (5%) 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).
   
   // break vs. continue
   #include <iostream>
   
   int main()
   {
       int i = 5, s = 5;
       for (i=0; i<9; i++)
       switch (i % 2)
       {
           case 0:
               s += 2;
               break;
           case 1:
               ++s;
               continue;
       }
       std::cout << s << std::endl;
       return 0;
   }
   
   
4. (5%) Assume the following code is compiled and run on an Intel x86 CPU.  The compiler allocates 4 bytes for each integer.  Please predict the output.
   
   // reinterpret_cast
   // Assume an x86 CPU and sizeof(int) == 4
   #include <iostream>
   using std::cout;
   using std::cin;
   using std::endl;
   
   int main()
   {
       int a[10] = { 0, 4, 9, 2, 9, 1, 5, 2, 2, 5 };
       int* p0 = a;
       int* p3 = &a[3];
       cout << p3 - p0 << '\t'
            << reinterpret_cast<char*>(p3) - reinterpret_cast<char*>(p0) << '\t'
            << *reinterpret_cast<char*>(p3) -
               *reinterpret_cast<char*>(p0)
            << endl;
       return 0;
   }
   
   
5. (5%) What will be the output of the following program?
   
   // cascaded function calls (P.468)
   #include <iostream>
   using std::cout;
   using std::cin;
   using std::endl;
   
   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 show() { cout << numerator << '/' << denominator << endl; }
       int numerator;
       int denominator;
   };
   
   int main()
   {
       Rational a(1, 5);
       a.show();
       a.setNumerator(2).setDenominator(7);
       a.show();
       return 0;
   }
   
   
6. (5%) What will be the output of the following program?
   
   // When is static objects destroyed
   #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)
   { static Object a(s);
     Object b("Bravo");
   }
   
   int main()
   {
       Object a("Alpha");
       f("Foxtrot");
       f("India");
       return 0;
   }
   
   
   
7. (5%) What will be the output of the following program?
   
   // Overloading Binary Operators
   #include <iostream>
   using std::cout;
   using std::endl;
   using std::ostream;
   
   class Rational {
   friend ostream& operator<<(ostream& output, const Rational& b) {
       output << b.numerator << '/' << b.denominator;
       return output;
   }
   
   public:
       Rational(int n=0, int d=1): numerator(n), denominator(d) {}
       Rational operator+(const Rational& b) {
           return Rational(numerator*b.denominator + denominator*b.numerator,
                   numerator * denominator);
       }
   private:
       int numerator;
       int denominator;
   };
   
   int main()
   {
       Rational a(1, 2);
       Rational b(1, 3);
       Rational c;
       c = a + b;
       cout << c << endl;
   
       return 0;
   }
   
   
8. (5%) 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).
   
   // vector of vector
   #include <iostream>
   #include <vector>
   using std::vector;
   using std::cout;
   using std::endl;
   
   int main()
   {
       typedef vector<int> Row;
       typedef vector<Row> Matrix;
       Row r(3);
       Matrix A;
       A.push_back(r);
       A.push_back(r);
       A.push_back(r);
       for (int i=0; i<3; ++i)
           for (int j=0; j<3; ++j)
               A[i][j] = 10*i + j;
       for (int i=0; i<3; ++i)
           cout << A[i].at(1) << ' ';
       cout << endl;
       return 0;
   }

9. (5%) 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).
   
   // Function Pointers (P.393)
   #include <iostream>
   
   int add(int a, int b)
   { return a + b; }
   
   int sub(int a, int b)
   { return a - b; }
   
   int mul(int a, int b)
   { return a * b; }
   
   int divide(int a, int b)
   { return a / b; }
   
   int main()
   {
       int *f[](int, int) = { add, sub, mul, divide };
   
       for (int i=0; i<4; i+=2)
       {
           std::cout << f[i](33, 5) << std::endl;
       }
   
       return 0;
   }
   

10. (5%) 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).

    // Polymorphism and Virtual Functions
    #include <iostream>
    using std::cout;
    
    class Polygon {
      protected:
        int width, height;
      public:
        void set_values (int a, int b)
          { width=a; height=b; }
    };
    
    class Rectangle: public Polygon {
      public:
        virtual int area()
          { return width*height; }
    };
    
    class Triangle: public Polygon {
      public:
        virtual int area()
          { return width*height/2; }
    };
    
    int main () {
      Rectangle rect;
      Triangle tri;
      Polygon* ppoly1 = &rect;
      Polygon* ppoly2 = &tri;
      ppoly1->set_values (4,5);
      ppoly2->set_values (4,5);
      cout << ppoly1->area() << '\n';
      cout << ppoly2->area() << '\n';
      return 0;
    }
    

11. (5%) For the following code, if we input "Game of Thrones" (without the quotation marks) and press ENTER, what will be the output?
    // cin, strlen, sizeof
    #include <iostream>
    #include <cstring>
    using std::cin;
    using std::cout;
    
    int main()
    {
        char s[20];
        cin >> s;
        cout << strlen(s) << '\t' << sizeof(s) << '\n';
        return 0;
    }
    
    
12. (5%) For the following code, if we input "Game of Thrones" (without the quotation marks) and press ENTER, what will be the output?
    
    // getline(), string.length()
    #include <iostream>
    #include <string>
    using std::cin;
    using std::cout;
    using std::string;
    
    int main()
    {
        string s;
        getline(cin, s);
        cout << s.length() << '\n';
        return 0;
    }
    
    
13. (5%) 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).
    
    // struct
    #include <iostream>
    
    struct Point {
        int x;
        int y;
    };
    
    int main()
    {
        Point p1 = {3, 4};
        Point p2 = {5, 4};
        std::cout << p1.x << p2.y << std::endl;
        return 0;
    }
    
    
14. (5%) 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).
    
    // Constructor
    #include <iostream>
    
    class Point {
    public:
        Point(int a = 4, int b = 5): x(a), y(b) {}  
    
        int x;
        int y;
    };
    
    int main()
    {
        Point p1(1, 2);
        Point p2(3, 4);
        Point p3(p1);
        std::cout << p1.x << p2.y << p3.y << std::endl;
        return 0;
    }
    
    
15. (5%) What will be the output of the following program?
    
    // for-loop
    #include <iostream>
    
    int main()
    {
        int sum = 0;
        int i;
        for (i=99; i>0; )  
            i = i - 1;
            sum += i;
    
        std::cout << i << '\t' << sum << std::endl;
        return 0;
    }
    
    
16. (5%) What will be the output of the following program?
    
    // while-loop
    #include <iostream>
    
    int main()
    {
        int total = 0;
        int n = 0;
        while (n <=100)
        {
            n += 2;
            total += n;
        }
        std::cout << n << '\t' << total << std::endl;
        return 0;
    }
    
    
    
17. (5%) What will be the output of the following program?
    
    // pass-by-reference
    #include <iostream>
    using std::cout;
    using std::endl;
    
    void f1(int& n)
    { cout << ++n; }
    
    void f2(int n)
    { cout << ++n; }
    
    int main()
    {
        int n = 1;
        cout << ++n;
        f1(n);
        f2(n);
        cout << ++n << endl;
    
        return 0;
    }
    
    
18. (5%) 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).
    
    // function overloading
    #include <iostream>
    using std::cout;
    using std::endl;
    
    int sum(int x, float y)
    {
        return x;
    }
    
    float sum(float x, int y)
    {
        return x;
    }
    
    int main()
    {
        cout << sum(2.5, 3) + sum(1, 1.5) << endl;
        return 0;
    }

19. (5%) 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).
    
    // Inheritance
    #include <iostream>
    
    class Base {
    public:
        Base(int n): value(n) {}
        int getValue() const { return value; }
    protect:
        int value;
    };
    
    class Derived: public Base {
    public: Derived(int n): Base(n) {}
    };
    
    int main()
    {
        Base a(4);
        Derived b(17);
        std::cout << a.getValue() << b.getValue() << std::endl;
        return 0;
    }
    

20. (5%) 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).

    // Recursion
    #include <iostream>
    using std::cout;
    
    void f(int a[], int i)
    {
        if (a[i] > 0)
        {
            f(a, i*2);        
            f(a, i*2+1);
            cout << a[i] << ' ';
        }
    }
    
    int main()
    {
        int a[32] = {15, 8, 4, 12, 2, 6, 10, 14, 1, 3, 5, 7, 9, 11, 13, 15 };
        f(a, 1);
        cout << std::endl;
        return 0;
    }