CS350 Intro Computer Systems Homework 1

Homework 1 on Reality Check

Write C programs to implement the reality we discussed last week. See the details of reality in the lecture notes: reality_1 on page 4, reality_3 on page 8 and reality_4 on page 12.

Submission: Put your source code, Makefile and screent screenshots in a doc file and generate a pdf file. Submit the pdf file on Canvas.

• Use the skeleton code reality.c for reality 1 and 3 and reality4.c for reality 4.
• Use Makefile for managing and compiling.
• When reality is executed, your program will make necessary decisions and print the following:

  
  $ reality 5
  
  reality_1_example_1_float: f=50000.000000
  f*f=2500000000.000000 >= 0
  
  reality_1_example_1_int: i=40000
  i*i=1600000000 >= 0
  
  reality_1_example_1_int: i=50000
  i*i=-1794967296 < 0
  
  reality_1_example_2_unsigned: uix=12 uiy=34 uiz=56
  ((uix+uiy)+uiz)=102 == (uix+(uiy+uiz))=102
  
  reality_1_example_2_signed: six=12 siy=34 siz=56
  ((six+siy)+siz)=102 == (six+(siy+siz))=102
  
  reality_1_example_2_float: fx=1.000000e+20 fy=-1.000000e+20 fz=3.140000
  
  ((fx+fy)+fz)=3.140000e+00 != (fx+(fy+fz))=0.000000e+00
  
  reality_3: n=5 iterations
  fun(0) -> 3.140000
  fun(1) -> 3.140000
  fun(2) -> 3.140000
  fun(3) -> 2.000001
  fun(4) -> 3.140000
  Segmentation fault (core dumped)
  
  $
   

• For reality_3, the number of iterations may vary depending on your compiler on your machine. It may even run well past 5 or 6.
• For reality_3, some of you might get "stack smashing detected" or something resembling, not seg fault.
• For those who don't seem to get seg fault, you need to turn off stack protector using -fno-stack-protector flag when compiling.
• When reality4 is executed, your program will compute the time taken to run the two functions copyij() and copyji(), and print them as follows:

  
  $ reality4
  
  copyij(): dim=2048: elapsed=0.13 secs
  
  copyji(): dim=2048: elapsed=0.97 secs
  
  $