Com S 229 Fall 2011

		     Problem Set 4 (16 pts)
		    
                          Due at 10:59am 
                        Friday, November 11



      	            Name: ___________________________


           ID (4-digit) : ___________



1. (2 points) Convert the following infix (or postfix) expressions to postfix (or infix):

   (a) (a + b) / (d - e) 






   (b) (b^2 - 4 * a * c) / (2 * a) 






   (c) a b c + * 




    

   (d) a b c d e + + * * e f - * 







2. (2 points) Write a function

       template <typename T>
       void split(const list<T>& aList, list<T>& list1, list<T>& list2); 

   that takes a list aList and creates two new lists, list1 and list 2. The object list1
   contains the first, third, fifth, and successive odd-numbered elements; list2 contains
   the even-numbered elements. 



































3. (4 points) 

   (a) Write a function 

       template <typename T> 
       T second (stack<T>& s); 

       that uses stack operations to return the second element from the top on
       the stack.  If s.size() < 2, throw the exception underflowError (which
       you may assume has been defined).
































   (b) Write a function 

       template <typename T> 
       void n2top(stack<T>& s, int n); 

       that moves the nth element (counting from the top, which is the 1st element) of the 
       stack to the top, leaving the order of all other elements unchanged.  For instance, 
       below is an integer stack before the action of n2top() on n = 4:   

                8  5  17  4  3  (top)

       After the action, it has the content: 

	        8  17  4  3  5  (top)































4. (4 points) What is the output of the following program

       #include <iostream>
       #include <string>

       using namespace std; 
       
       class baseCL
       {
       public: 
	   baseCL(string s, int m = 0): msg(s), n(m)
	   {}

	   void output()
	   { cout << n << " " << msg << endl; }
	   
       private: 
           string msg; 

       protected: 
           int n; 
       };


       class derivedCL: public baseCL
       {
       public: 
           derivedCL(int m = 1): baseCL("Base", m-1), n(m)
	   {}

	   void output()
	   {
	       cout << n << endl; 
	       baseCL::output(); 
	   }

       private:
           int n; 
       }; 

       int main()
       {
           baseCL bObj("Base Class", 1); 
	   derivedCL dObjA(4), dObjB; 

	   bObj.output(); 
	   dObjA.output(); 
	   dObjB.output(); 

	   return 0; 
        }










5. (4 points) Consider the following classes: 
        
        class baseCL
	{
	public: 
	    baseCL(int a): one(a)
            {}

	    virtual void identify()
	    { cout << one << endl; }

	protected: 
	    int one; 
        }; 

	class derivedCL: public baseCL 
	{
	public: 
	    derivedCL(int a, int b): baseCL(a), two(b)
	    {}

	    virtual void identify()
	    { cout << one << " " << two << endl; }

	protected: 
	    int two; 
        }; 

    The following functions are used to identify the classes: 
        
        void announce1(baseCL x)
	{
	    x.identify(); 
	}

        void announce2(baseCL *x)
	{
	    x->identify(); 
	}

    (a) (2 points) Give the output of the following code segment: 

        baseCL baseObj(7), *p; 
	derivedCL derivedObj(1, 2); 

	announce1(baseObj); 
	announce2(&derivedObj); 
	p = &derivedObj; 
	p->identify(); 

 









    (b) (2 points) Give the output of the following code segment

        baseCL *arr[3]; 
	derivedCL derivedObj(3, 5); 

	announce1(derivedObj); 
	announce2(&derivedObj); 
	for (int i=0; i<3; i++)
	    if (i==1)
	        arr[i] = new baseCL(7); 
	    else
	        arr[i] = new derivedCL(i, i+1); 
	for (i=0; i<3; i++)
	    arr[i]->identify();