Com S 229 Fall 2011

                         Problem Set 2 (10 pts)
		    
                          Due at 10:59am 
                        Wednesday, October 5



      	            Name: ___________________________


           ID (4-digit) : ___________



1. (1 point) Find the greatest common divisor of 462 and 1260. 






















2. (2 points) Correct all the errors in the definitions and usage of the two
    classes Circle and Rectangle below.  You should make as few changes to the
    original code as possible.  (You may cross out erroneous portions of the
    code and show their corrections, if any, beside in clear handwriting.) 


        const float PI = 3.14159; 

        class Circle 
        {
        public: 
            int Circle( float r ) : radius(r); 
            Circle( float r1 = 0 ) { radius = r1; } 
            float Area(void) const;  
            float getRadius() { return radius; }

        private:
            float area, radius;    
        }

        float Area(void) 
        { 
            area = PI * radius * radius; 
            return area;
        }

        class Rectangle 
        {
        public: 
            Rectangle (float l; float w) : length(l), width(w) 
            {}
            float Area() const 
            { return length * width; }

        private: 
            float length, width; 
        };


        void main() 
        {
            Circle a(3.1); 
            Rectangle b; 
	
            b = Rectangle(5, 4); 
    
            cout << "Circle a has radius " << a.radius
                 << "and area "  << a.Circle::Area()
                 << "." << endl; 

            cout << "Rectangle b has area " << b.Circle::Area()
                 << "." << endl; 
        }






3. (2 points) The box class provides measurement of a box that is defined by its 
   length, width, and height. Store the base of the box as a rectangle object
   using object composition.  

       	class box
        {
        public: 
            box(double l, double w, double h): ________________, height(h)
            {}

            double volume() // length * width * height

            { ____________________________ }

            double getHeight()
            { return ________________________ }

        private: 
            Rectange base;  // use the Rectangle class defined in the notes
	    double height; 
        }; 


   (a) Complete the initialization list for the constructor so that the
       Rectangle object base gets initialized. 


   (b) Give the return value for getHeight(). 





   (c) Implement the member function volume. 

















4. (5 points) Begin with the following declaration and inline implementation of
   the accumulator class. 

        class accumulator 
	{
	public: 
	    // constructor initializes total 
	    accumulator (int value = 0) : total(value)
	    {}

	    // access function
	    int getTotal()
	    { return total; }

	    // update the data member total 
	    void addValue(int value) 
	    { total += value; } 

	private:
	    // total accumulated by the object 
	    int total; 
        }; 

    (a) Add the overloaded operator += that has the same function as
        addValue(). Include both the prototype for the operator and its
        implementation as an external function. 












    


    (b) Add the negation operator, -, to the class.  The operator changes the
        sign of the current value for total. Give the function prototype and 
        the implementation as an external function. 









          
        





    (c) Add the + operator as a friend function.  The operator takes two
        accumulator objects as arguments and returns a new accumulator object
        whose value is the sum of the data members.  Include both the prototype
        and the implmentation as an external function. 
















    (d) Add an overloaded version of the output operator <<. Include both the
        prototype and the implementation as an external function. 















    (e) What is the output in the following code segment? 

          accumulator x(5), y(3), z(-9), w; 

	  x += 3; 
	  w = x + y; 
	  z = -z;  

          cout << w << " " << z << endl;