EECS 1012 Lecture Notes - Lecture 7: Radio Button, Sport Utility Vehicle

After successfully completing this assignment, students will be able to:

• Configure, run, and test a linux server in AWS' EC2
• Configure, run, and test a Windows server in AWS' EC2

1. Create an Ubuntu 20 LAMP server in EC2 like we did in class.
2. Verify your that Apache was installed by opening your browser and enter the public dns of your server in the address bar. If it does not connect either you did not add HTTP to the Security Group, or the install did not work properly. Take a screenshot and save it (for submission below).
3. The default location of html and php files is /var/www/html. Change to that directory. Now, using your favorite text editor use sudo to run your editor and create a file in that directory named info.php. For example, sudo nano info.php Then enter the following in that file to show information about the PHP installation: <?php phpinfo(); ?> Save the changes to the file and exit the editor.
4. Now in your browser, enter the public dns of your server in the address bar / info.php. For example, my public dns was ec2-54-89-230-235.compute-1.amazonaws.com, so I enter  as the url. Take a screenshot and save it (for submission below).
5. Create a Windows 2016 Server, like we did in class.  
6. Login to it using Remote Desktop.  Take a screenshot of Remote Desktop connected to your Windows Server and save it (for submission below).

Now that you have completed the assignment, stop or terminate your EC2 instances. Stopping them means that it is now longer running, but your data is saved. That means you will not accrue charges on your running server. Terminating will both stop and delete the instances (also not accruing charges).

• Screenshot of Apache page on your server shown in your browser
• Screenshot of the PHP info page on your server shown in your browser
• Screenshot of Remote Desktop session to your Windows Server

5. Consider the following class: import java.util.Scanner; public class Money private int dollars; private int cents; public Money (int d, int c) { dollars = d; cents = c; /* Point 1 */ public String toString() { String result; if (cents > 100) int totalCents = dollars * 100 + cents; dollars = totalCents / 100; cents = total Cents % 100; /* Point 2 */ /* Point 3 */ result = "$" + dollars + ", " + cents + "C"; return result; public static void main(String[] yourGrandfather) Scanner keyboard - new Scanner (System.in); Money amount; int C; /* Point 4 */ System.out.print("Enter an amount in cents: "); C = keyboard.nextInt (); amount = new Money (c/ 100, CX 100); System.out.println("You have: " + amount.toString()); The above program compiles and runs without error. Which variables are in scope at each of the points marked by comments in the above class? In other words, if each of these comments were replaced by an actual Java statement, which variables could be used in this statement without a prefix (that is, without having to write the name of a class or other variable in front of the variable name) and without the compiler reporting an unknown variable error? List each variable that is in scope at each of the points marked by comments in the above class, and indicate whether it is an instance variable, a formal parameter, or a local variable. Note that you will be penalized for every variable that is out of scope at a given point but that you list as being in scope at that point.

1.Write a function encipher(s, n) that takes as inputs an arbitrary string s and a non-negative integer n between 0 and 25, and that returns a new string in which the letters in s have been "rotated" by n characters forward in the alphabet, wrapping around as needed. For example:

>>> encipher('hello', 1) result: 'ifmmp'

>>> encipher('hello', 2) result: 'jgnnq'

>>> encipher('hello', 4) result: 'lipps'

Upper-case letters should be "rotated" to upper-case letters, even if you need to wrap around. For example:

>>> encipher('XYZ', 3)

result: 'ABC'

Lower-case letters should be "rotated" to lower-case letters:

>>> encipher('xyz', 3)

result: 'abc'

Non-alphabetic characters should be left unchanged:

>>> encipher('#caesar!', 2)

result: '#ecguct!'

Hints/reminders:

You can use the built-in functions ord and chr convert from single-character strings to integers and back:

>>> ord('a')

result: 97

>>> chr(97)

result: 'a'

You can use the following test to determine if a character is between 'a' and 'z' in the alphabet:

if 'a' <= c <= 'z':

A similar test will work for upper-case letters.

We recommend writing a helper function rot(c, n) that rotates a single character c forward by n spots in the alphabet. We have given you a template for this helper function in ps3pr3.py that checks to ensure that c is a single-character string. We wrote rot13(c) in lecture; rot(c, n) will be very close to rot13(c)! You can test your rot(c, n) as follows:

>>> rot('a', 1)

result: 'b'

>>> rot('y', 2)

result: 'a'

>>> rot('A', 3)

result: 'D'

>>> rot('Y', 3)

result: 'B'

>>> rot('!', 4)

result: '!'

Once you have rot(c, n), you can write a recursive encipher function.

Once you think you have everything working, here are three more examples to try:

>>> encipher('xyza', 1)

result: 'yzab'

>>> encipher('Z A', 2)

result: 'B C'

>>> encipher('Caesar cipher? I prefer Caesar salad.', 25)

result: 'Bzdrzq bhogdq? H oqdedq Bzdrzq rzkzc.'

2.Write a function decipher(s) that takes as input an arbitrary string s that has already been enciphered by having its characters "rotated" by some amount (possibly 0). decipher should return, to the best of its ability, the original English string, which will be some rotation (possibly 0) of the input string s. For example:

>>> decipher('Bzdrzq bhogdq? H oqdedq Bzdrzq rzkzc.')

result: 'Caesar cipher? I prefer Caesar salad.'

Here are two more examples:

>>> decipher('Hu lkbjhapvu pz doha ylthpuz hmaly dl mvynla lclyfaopun dl ohcl slhyulk.')

result: 'An education is what remains after we forget everything we have learned.'

>>> decipher('python')

result: 'eniwdc'

------------------------------------

def rot(c, n):
    """ your docstring goes here """
    # check to ensure that c is a single character
    assert(type(c) == str and len(c) == 1)

def letter_prob(c):
    """ if c is the space character (' ') or an alphabetic character,
        returns c's monogram probability (for English);
        returns 1.0 for any other character.
        adapted from:
       
    """
    # check to ensure that c is a single character   
    assert(type(c) == str and len(c) == 1)

    if c == ' ': return 0.1904
    if c == 'e' or c == 'E': return 0.1017
    if c == 't' or c == 'T': return 0.0737
    if c == 'a' or c == 'A': return 0.0661
    if c == 'o' or c == 'O': return 0.0610
    if c == 'i' or c == 'I': return 0.0562
    if c == 'n' or c == 'N': return 0.0557
    if c == 'h' or c == 'H': return 0.0542
    if c == 's' or c == 'S': return 0.0508
    if c == 'r' or c == 'R': return 0.0458
    if c == 'd' or c == 'D': return 0.0369
    if c == 'l' or c == 'L': return 0.0325
    if c == 'u' or c == 'U': return 0.0228
    if c == 'm' or c == 'M': return 0.0205
    if c == 'c' or c == 'C': return 0.0192
    if c == 'w' or c == 'W': return 0.0190
    if c == 'f' or c == 'F': return 0.0175
    if c == 'y' or c == 'Y': return 0.0165
    if c == 'g' or c == 'G': return 0.0161
    if c == 'p' or c == 'P': return 0.0131
    if c == 'b' or c == 'B': return 0.0115
    if c == 'v' or c == 'V': return 0.0088
    if c == 'k' or c == 'K': return 0.0066
    if c == 'x' or c == 'X': return 0.0014
    if c == 'j' or c == 'J': return 0.0008
    if c == 'q' or c == 'Q': return 0.0008
    if c == 'z' or c == 'Z': return 0.0005
    return 1.0