Python assignment – Cheap Research Essays

Python assignment
You should submit ONLY one doc (or docx or pdf) file named assign4.doc (or .docx or .pdf). Any other file format (like .py, .zip, .rar, etc.) is not allowed. This file should contain your python code for the program(s) and the screen shot(s) of your program’s sample runs (with output). Make sure to put your python code correctly in this file (with correct indentation). If you have any text for the grader to read before grading, you can include it at the top of this file.
You must use Python 3.x to implement these programs.
Your grade will be based on functionality (does the program do what it is suppose to do) and understandability (are the literals meaningful and is the code modular and well documented with appropriate comments).
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Part – I (5 points)

This part of the assignment contains multiple subparts. Make sure to complete all subparts to get full credit. You must use (nested) loops to program the solution to problems mentioned below. You are not allowed to use print statements that print multiple numbers at the same time. For example: to print numbers from 0 to 9 in the same line, you are not allowed to use:

print(0,1,2,3,4,5,6,7,8,9) or print(“0 1 2 3 4 5 6 7 8 9”)

Instead you should use:

for i in range(10):

print(i, end = “ “)

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1) Part a: Write code that will print the following:

0 1 2 3 4 5 6 7 8 9

HINT: You need to use two for loops (one nested inside the other). First, create a loop that prints the first line (DO NOT PRINT USING print(“0 1 2 3 4 5 6 7 8 9”)). Then enclose it in another loop that repeats the line 10 times. Use either i or j variables for what the program prints. This problem and the next one helps reinforce what those index variables are doing.

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Part b: Adjust the prior program to print:

0 0 0 0 0 0 0 0 0 0

1 1 1 1 1 1 1 1 1 1

2 2 2 2 2 2 2 2 2 2

3 3 3 3 3 3 3 3 3 3

4 4 4 4 4 4 4 4 4 4

5 5 5 5 5 5 5 5 5 5

6 6 6 6 6 6 6 6 6 6

7 7 7 7 7 7 7 7 7 7

8 8 8 8 8 8 8 8 8 8

9 9 9 9 9 9 9 9 9 9

2) Write code that will print the following:

0 1

0 1 2

0 1 2 3

0 1 2 3 4

0 1 2 3 4 5

0 1 2 3 4 5 6

0 1 2 3 4 5 6 7

0 1 2 3 4 5 6 7 8

0 1 2 3 4 5 6 7 8 9

HINT: This is same as problem (1), but the inside loop no longer loops a fixed number of times. Don’t use range(10), but adjust that range amount.

Extra Credit (2 points):

Write a Python program that will print the following:

11 12

13 14 15

16 17 18 19

20 21 22 23 24

25 26 27 28 29 30

31 32 33 34 35 36 37

38 39 40 41 42 43 44 45

46 47 48 49 50 51 52 53 54

• Generate the output using two for loops, one nested.

• Create a separate variable to store numbers that will be printed.

This problem requires a bit of an “a-ha” to get. Make sure to ask around if you have problems.

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Part – II (5 points)

Decoding a secret message:

The description may seem daunting, but the solution is not that hard. You can use the built-in string datatype with the associated built-in functions and while loop (with ‘len’ function) or a for loop (with ‘in’ operator) to traverse the string. Also, use the ’chr’ and ’ord’ functions (which are based on ASCII code) discussed in course material. Make sure to look at the examples in the course material and do #18 and #19 in Exercises 2. Answer for #19 is provided and it can give valuable hints for solving this problem.

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Your country is at war and your enemies are using a secret code to communicate with each other. You have managed to intercept a message that read as follows:

:mmZ\dxZmx]Zpgy

The message is obviously encrypted using the enemy’s secret code. You have just learned that their encryption method is based upon the ASCII code (you can find this set easily by searching online). Individual characters in a string are encoded using this system. For example, the letter ‘A’ is encoded using the number 65 and ‘B’ is encoded using the number 66.

Your enemy’s secret code takes each letter of the message and encrypts it as follows (using a secret key):

If (OriginalChar + Key > 126) then

EncryptedChar = ((OriginalChar + Key) – 127) + 32

Else

EncryptedChar = (OriginalChar + Key)

For example, if the enemy uses Key = 10 then the message ”Hey” would be encrypted as:

Character ASCII

H 72

e 101

y 121

Encrypted H = (72 + 10) = 82 = R in ASCII

Encrypted e = (101 + 10) = 111 = o in ASCII

Encrypted y = 32 + ((121 + 10) – 127) = 36 = $ in ASCII

Consequently, “Hey” would be transmitted as “Ro$”.

Write a program that decrypts the intercepted message. You only know that the key used is a number between 1 and 100. Your program should try to decode the message using all possible keys between 1 and 100. When you try the valid key, the message will make sense. For all other keys, the message will appear as gibberish.

HINT: You will need to implement a decrypt function that takes in an encrypted message as string and a key as integer and returns the decrypted message as string. You can decrypt each letter of the message as follows:

If (EncryptedChar – Key < 32) then

DecryptedChar = ((EncryptedChar – Key) + 127) – 32