Description

Practical Examination 1
Time allowed: 2 hours
Instructions (please read carefully):

1. This is an open-book exam. You are allowed to bring in any course or reference materials in printed form. No electronic media or storage devices are allowed.
2. This practical exam consists of two questions. The time allowed for solving this test is 2 hours.
3. The maximum score of this test is 20 marks. Note that the number of marks awarded for each question IS NOT correlated with the difficulty of the question.
4. You are advised to attempt all questions. Even if you cannot solve a question correctly, you are likely to get some partial credit for a credible attempt.
5. While you are also provided with the templates q1-template.c and q2-template.c to work with, your answers should be submitted on Coursemology. Note that you can only run the test cases on Coursemology for a limited number of tries because they are only for checking that your code is submitted correctly. You are expected to test your own code for correctness locally on VS Code and not depend only on the provided test cases. Do ensure that you pasted your answers correctly by running the test cases at least once.
6. In case there are problems with Coursemology.org and we are not able to upload the answers to Coursemology.org, you will be required to name your file q1-<student no>.c and q2-<student no>.c where <student no> is your student number and leave the file in the tic1001-pe1 folder on the Desktop. If your file is not named correctly, we will choose any .c file found at random.
7. Please note that it shall be your responsibility to ensure that your solution is submitted correctly to Coursemology and correctly left in the desktop folder at the end of the examination. Failure to do so will render you liable to receiving a grade of ZERO for the Practical Exam, or the parts that are not uploaded correctly.
8. Please note that while sample executions are given, it is not sufficient to write programs that simply satisfy the given examples. Your programs will be tested on other inputs and they should exhibit the required behaviours as specified by the problems to get full credit. There is no need for you to submit test cases.
ALL THE BEST!
Question 1: 7-Up! [10 marks]
A number game is played where players in a circle count off from 1, i.e. the first player says “1”, and the next will say “2”, and so on, going multiple times around the circle until someone loses. However, if the number is a multiple of 7 or contains the digit 7, the player has to say “7-Up” instead of the number.
To make the game harder, if the number is BOTH a multiple of 7 and contains the digit 7, the player has to say “Double-Up” instead.
You decide to use your newly acquired programming knowledge to write a program to help you win this game. However, it is possible that the game might use a different digit from 7, so your program has to be general enough to work with all digits from 1 to 9.
A. Contains Digit
Implement the function bool contains_digit(int n, int d) that returns true if the positive integer n contains the digit d, and false otherwise. [5 marks]
Sample tests:
Test function
Output
contains_digit(12345, 2) true
contains_digit(1234567890, 0) true contains_digit(1010101, 1) true contains_digit(12345, 7) false contains_digit(987654321, 0) false

B. Simulating the Game
Implement the function void play(int start, int stop, int d) which takes in the starting and ending number, and digit of play. It should display (i.e. print on the screen) line-byline, the appropriate thing to say for the numbers from start to end inclusive following these rules:
• “Double-Up” if n is a multiple of d and contains the digit d
• “d-Up” (where d is the actual digit) if n is either a multiple of d or contains the digit d.
• the number n, if otherwise.
Notes:
3. The maximum int bound will not be exceeded in the computation.
[5 marks]
Sample tests (on next page):
play(30, 45, 4);
30
31
4-Up 33
4-Up 35
4-Up
37
38
39
Double-Up
4-Up
4-Up
4-Up
Double-Up
4-Up play(690, 710, 7);
690
691
692
7-Up
694
695
696
7-Up
698
699
Double-Up
7-Up
7-Up
7-Up
7-Up
7-Up play(25,45, 3);
25
26
3-Up
28
29
Double-Up
3-Up
3-Up
Double-Up
3-Up
3-Up
Double-Up
3-Up
3-Up
Double-Up
40
7-Up 41
Double-Up 3-Up
7-Up 3-Up
7-Up 44
7-Up 3-Up
C. Bonus Question
This question gives 2 additional bonus marks.
Implement the function contains_double(int n) which takes in a positive integer n, and returns true if n contains at least two consecutively identical digits, and false otherwise.
Sample tests:
Test function Output

contains_double(12345) false contains_double(123123) false contains_double(112233) true contains_double(333333) true contains_double(120021) true

Question 2: Bacteria [10 marks]
Dr. Wink is currently researching a medicine to control the population of the bacteria Ccisscari. You are asked to tabulate the experiment results.
The Ccisscari bacteria doubles its number every generation. Dr. Wink’s medicine, applied every G generations, can kill off K% of the bacteria.
Below is an example experiments for 10 generations, with 50 Ccisscari bacteria in the beginning, and the medicine was applied every 3 generations to kill off 10% of the bacteria:
Generation Population Kill New population
1 50 0 100
2 100 0 200
3 200 20 360
4 360 0 720
5 720 0 1440
6 1440 144 2592
7 2592 0 5184
8 5184 0 10368
9 10368 1036 18664
10 18664 0 37328
At the end of the simulation, there were 37328 bacteria left.
Your task is to implement the function int simulate that takes the following inputs:
• int start_population: The initial population of the bacteria.
• int end_generation: Total number of generations to simulate.
• int G: The interval to apply the medicine.
• int K: The effect of the medicine, in percentage.
This function returns the remaining bacteria at the end of the simulation. For example, simulate(50, 10, 3, 10); gives the answer 37328.
Several notes:
1. The medicine is applied before the population doubles.
2. The medicine effect should be rounded down to the nearest integer (as you cannot kill a fraction of a bacteria).
3. You can assume that the maximum int bound will not be exceeded in the computations.
[10 marks]
Sample tests (on next page):
Test function Output
simulate(50, 10, 3, 10) 37328
simulate(1, 20, 1, 50) 2
simulate(100, 8, 4, 90) 256
simulate(10, 50, 12, 100) 0

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