CS 354, version A
Fall 2011 		Name:___________________
Section:________________
ID:___________________
Exam 1
No electronic devices may be used while taking this exam. No calculators, no cell phones. Each student is allowed one 8.5 by 11 inch sheet of paper with handwritten notes.

Show all work, and do any/all calculations on the exam. Extra scratch paper may not be used. Partial credit will be given based on work shown.

Exam Score
Q1 = _____ / 20
Q2 = _____ / 20
Q3 = _____ / 9
Q4 = _____ / 8
Q5 = _____ / 11
Q6 = _____ / 32
Total = _____ / 100		 










Question 1 (20 points)


The following C program is to be compiled on one of the CS department's
instructional Linux machines 




#include <stdio.h>
#include <stdlib.h>

int main(                                                ) {
   int i;
   int converted;

   for ( i = 0; i < argc; i++ ) {
      converted = atoi(*(argv + i));
      printf("argv[%d] is %d\n", i, converted );
   }

   return 0;
}





Part A (8 points)
The parameters to main() are missing.
Provide these parameters in the space provided on the code fragment.

 

Part B (12 points)

With the correct parameters, this program is to be compiled with:
  cc -o testarg testarg.c  

Then, this program is invoked with the command line


    testarg  99 4 500




What is the output of this program?

 


 





Question 2 (20 points)


Name the four segments of memory provided to each executing program:

    

  1.  

    

  2.  

    

  3.  

    

  4.  

    



Question 3 (9 points)


Name the 3 types of shift operations:

    

  1.  

    

  2.  

    

  3.  

    



Question 4 (8 points)


An assembly language instruction is to be used to 

selectively set the middle two bytes of a 32-bit variable

called  fourbytes.
The instruction to do this operation is


    or  fourbytes, mask, fourbytes



Give the value of  mask in hexadecimal.

 


 


 



Question 5 (11 points)


Write the smallest fragment of C (declarations and) code that you can think
of that contains a buffer overflow programming error. 

 


 


 


Question 6 (32 points)


Consider this C program.  It compiles without warnings or errors.



int a(int *x, int *y, int z) {

  z = *y - 2;
  *x = 707;
  return (*y + z);
}


int main() {
   int j, k, l, m;
   int *ptr;

   j = 12;
   ptr = &k;
   *ptr = 32;
   l = j * 2;
   m = a(&j, ptr, l);

   return 0;
}



There are 8 variables declared and used in this program. 
Trace through the entire program, 
and show the value of every variable, as well as how each variable
changes as the program executes.
When a variable's value changes,
draw a / over its current value, and then write the new
value of the variable. 
Use arrows to show pointer values. 



         x                           j


         y                           k


         z                           l


                                     m


                                     ptr