CS 202, Fall 2007


Assignment #7: 10 Points.

Due Date: Tuesday, 11/6/07.


(3)  1.	In HW #3, Problem 3, the load() function of the Simpletron simulator 
	was modified to read and load SML programs from a text file named 
	"prog.sml". Each line of the SML program file consists of a 4 digit 
	opcode and is terminated with a line containing the code -99999. 
	Modify the input functions to read an optional text field comment  
	of no more than 60 characters which follows the numeric opcode.  
	Use the getline() member function (see pg 445 and Figure 15.6) to read 
	the comment following the numeric opcode to the end of the line.  

	The load() function must read and print each opcode followed by
	the comment field to create a listing of the SML program.  The modified 
	function must count the input lines in order to print line numbers 
	before each line as the program file is read, and then run the 
	program in the same manner as before. 

	Test your modifications using the SML program Example 1 in Figure
	8.40 (pg 466) run from a file.  Include the opcode mnemonics shown 
	in the text example as comments in the SML program file.  Turn in 
	the output from the test run along with the commented portions of 
	the simulator source code which were modified.**

(2)  2. Exercise 12.5.

(2)  3. Compile and run the program st.cpp from the Lecture Examples on the
        course website.  What happens when the line 'peoptr = &Fred;' is 
        commented out?  Why?**

(2)  4. Modify the program st.cpp from the Lecture Examples on the course 
        website to add a new class called "grad_student" which is derived 
        from "student" and inherits attitude_is() from student.  The 
        grad_student attitude_is() should be: "Graduate students think CS 
        is fun", but the grad_student class must NOT redefine the attitude_is() 
        member functions from either base class.  Modify the main program 
        to create an object from the grad_student class and print the attitude 
        directly and also by using a pointer to the grad_student class.  
        The attitudes of the "people" and "student" classes must remain 
        unchanged. Hand in your source code and program output.**

(1)  5. Discuss why converting a base-class pointer to a derived-class 
        pointer using a static_cast (compile-time downcasting) is considered
        dangerous.


      **For full credit, turn in fully commented program listings,
        including your name and the problem number, and the output
        from test runs exactly as produced by the program.