Name: Frank Wan
UserID: cs30xqm

Description
-----------
This program welcomes the user to CSE 30, Winter 2017.
Then it states the due date of the assignment,
and squares the number given as an argument.

How To Compile
--------------
The user must be in the program's directory, where all the
source code is located along with the Makefile.
Then, the user types 'make'

How To Run
----------
The user types the executable name followed by an integer.
Example input: ./a.out 5

Normal Output
-------------
[cs30xqm@ieng9]:pa0:80$ ./a.out 5
Welcome to CSE 30, Winter 2017
PA0 is due on January 17, 2017
The square of 5 is 25

Normal output is printed to stdout.

Abnormal Output
---------------
If the user does not provide arguments:

[cs30xqm@ieng9]:pa0:85$ ./a.out
./a.out: missing integer arg
Usage: ./a.out [INTEGER]
 Integer value to square

If the user provides too many arguments:

[cs30xqm@ieng9]:pa0:90$ ./a.out 5 5
./a.out: too many arguments
Usage: ./a.out [INTEGER]
 Integer value to square

Abnormal output is printed to stderr.

Testing
-------
Using the sample pa0test executable, we can compare the output of pa0test
and this program using the diff tool. If there is no difference
in output on the same input, this program has the correct output.

Questions
---------
0) Why is it considered an integrity violation if a student submits code copied
from someone/somewhere else?

We agreed and signed that we would only submit work that is a truthful
demonstration of our own knowledge and abilities.

1) List the 4 compilation errors and 1 compilation warning you found in the
source files. Please include the name of the file that consists the error,
the line number, and your fix for the error.

Error 1:
  File: pa0.c
  Line Numbers: 56, 57
  Fix: Added #include <stdio.h> for fprintf function

Error 2:
  File: pa0.c
  Line Numbers: 102
  Fix: Added & in front of dueDate

Error 3:
  File: pa0.c
  Line Numbers: 109
  Fix: Missing a return, so added return 0;

Error 4:
  File: printDueDate.c
  Line Numbers: 32, 34
  Fix: Added #include "pa0.h" for DueDate struct

Warning 1:
  File: pa0.c
  Line Numbers: 108
  Fix: changed argv[NUM_TO_SQUARE_INDEX] to argVal

2) Why is the program not printing the correct output when you first run it
after successful compilation? How did you fix it?

The program was decrementing argVal instead of argc, so argc would not be
equal to EXPECTED_ARGS, which triggered error messages being printed.

3) What line of C code do you see printed to the screen?

45        int argVal = 0;            /* Value to square from command line */

4) What happens if you type nexti at this point? Why?

(gdb) nexti
50        --argc;
1: x/i $pc
=> 0x10cfc <main+16>:   ld  [ %fp + 0x44 ], %g1

nexti executes the next line of machine code, which would be decrementing argc.

The second dueDate.day says 17, because it is printed after the line
dueDate.day = DUEDATE_DAY;
is executed

5) Type x/s $i0. What does this do? What do you see printed to the screen?

This prints what is stored inside $i0:

(gdb) x/s $i0
0x109f0:        "Winter 2017"

6) What is a breakpoint? How do you set one? (You did this earlier)

A breakpoint is where the debugger stops when that point is reached.

We can set a breakpoint by typing 'break [function]' or 'break [line number]'

Earlier we did break main, which sets a breakpoint in main()

7) What function are you debugging if gdb displays the following?

<foobar+32>: sethi %hi(0x20400), %o6

We are debugging function foobar

8) What is the difference between step and next? What is the difference between
step/next and stepi/nexti?

Step goes into any function, while next goes over them
Step/next looks at the source code, while stepi/nexti look at machine code

9) What are $o0, $i0, etc, referring to?

They are referring to registers.

10) What is the difference between the x and p commands? Which should you use to
look at the contents of a register? Which should you use to look at something in
memory? What do x/s and p/d mean (what do the /s and /d specify)?

x prints things stored in memory, while p prints named variables

You should use x for looking at contents of a register and something in memory.

The /s in x/s means display as a null terminated string
The /d in p/d means display as a signed integer

11) How do you remove a file from git tracking (without actually deleting the file)?

git rm --cached [file]

12) How do you view the list of commits you've made?

git log

13) How do you force Git to ignore a file or all of the files with a specific extension?

In the .gitignore file, make a new line with the file you want git to ignore.
For file extensions, do the same but with *.[file extension]

14) What is the name of the directory that contains the Git metadata for your repository?

.git

15) After a successful call to strtol(), why should endptr point to the null character?

It means the entire string was successfully processed. If there was an error,
it would point to the first invalid character.