Anatomy of a computer program

Posted on January 11, 2024 by Administrator Posted in A Level Concepts, A Level Quiz, Coding Quiz, Computer Science, Computing Concepts, Computing Terminology Quiz, GCSE Concepts, GCSE Quiz, Quizzes

Computer programs are a set of step-by-step instructions used to teach the computer how to complete a task.

Computer programs are written using a specific programming language. Nowadays, most programmers would write code using a high-level programming language such as Python, C, C#, Java, Ruby or Basic.

If we were to dissect a computer program, we would find the following elements:

Reserved Keywords & Built-in Functions
Identifiers (e.g. for variables and subroutines)
Values of different data types
Computing Operators
Punctuation signs
Comments/Annotations

Let’s investigate these elements further… Click on the sub sections below to find out more.

Reserved Keywords & Built-in Functions

The reserved keywords are defined by the language used to write your code. As opposed to a foreign language like French or Spanish, high level programming languages such as Python or Java only have a few dozen reserved keywords.

For instance, in Python 3.6 there are 33 reserved keywords and a few built-in functions such as print,input,str,int,float.

Here is a non-exhaustive selection of some of the most useful Python reserved keywords and built-in functions.

Reserved Keywords:

if	elif	else
while	break	continue
for	in	as
import	from	global
def	return	local
class	del	none
try	except	raise

Built-in Functions:

print	input	range
str	int	float
min	max	round
len	chr	ord

Identifiers (e.g. for variables and subroutines)

Identifiers are the name the programmers will choose when creating a variable, a constant, a function or a procedure. For instance, when storing the score of a game using the following line of code:

score = 0

score is the identifier of the variable that stores the score of the player.

Note that a programmer cannot used reserved keywords or built-in functions as identifiers in a program.

For instance in python you cannot have a variable called while as input is a reserved keyword of the language.

Note that, with Object-Oriented Programming languages, you will also use identifiers to give a name to your classes and objects.

Values of different data types

The values are the pieces of data used in a program. They can be hardcoded within the code or retrieved as input.

Each value as its own data type:

String values which contain a alphanumerical characters e.g. “James”, “Bond”, “007”
Integer values which contain whole numbers (positive or negative) such as 365 or -10
Float values (aka Real) which contain numbers which can have a decimal point such as: 3.14 or 9.81
Boolean values which are either True or False

Notice how, when using a string value in your code, you have to use “speechmarks”. This is because you do not want your computer to be confused between reserved keywords, identifiers and string values.

Computing Operators

There is a range of different operators that can be used in a computer program including:

The Assignment Operator =, used to assign a value to a variable or a constant e.g.
score = 0
Arithmetic Operators +, –, *, /, **, //, % used to perform arithmetic calculations
Comparison Operators <, >, <=,>=, ==, !=
Boolean Operators and, or, not

Punctuation signs

Each language has its own syntax and its own set of punctuation signs. In the English language the example of punctuation signs are the comma ,, the full stop., the question mark ?. And syntax in a language do matter as omitting or using the wrong punctuation sign it can alter the meaning of a message. For instance, would you go swimming in these waters, knowing that “crocodiles do not swim here”?

Programming languages have their own syntax too. Not using the correct syntax in your code will generate a syntax error. This means that your computer cannot interpret your code and hence will not run it.
In Python, the main punctuation signs are the brackets (, ), [, ], { and } the colon : and the comma ,.

Comments/Annotations

Finally, most programs will include some comments (aka annotations). These are optional and are only for the benefit of the programmers who will read and work on your code. Comments provide key explanations of what a section of code is doing. Comments will be completely ignored by the computer.

In Python, comments have to start with a # sign. e.g.

#This is a single-line comment

You can also create comments over multiple lines using a triple quote: “””. e.g.

""" 
    This is a multi-line comment.
    You can add much more information here.
    These are often used at the top of your code to specify:
         - the version number, 
         - the date the code was last updated
         - copyright information.
"""

Your Task

Your task is to identify all the different elements of the short program below, and drag them in the corresponding sections.
Anatomy of a Computer Program – Drag and DropOpen in New Window

The Von Neumann Processor Architecture

Posted on January 8, 2024 by Administrator Posted in A Level Concepts, A Level Quiz, Computer Hardware, Computer Science, Computing Concepts, GCSE Concepts, GCSE Quiz, Quizzes

John Von Neumann (1903-1957) was a Hungarian-American mathematician, physicist and computer scientist and a founding figure in computer science, with significant contributions to computing hardware design.

The Von Neumann architecture refers to a processor architecture which has access to a program stored in primary memory as a set of instructions. A processor based on the Von Neumann architecture can execute these instructions sequentially using the Fetch Decode and Execute cycle (FDE Cycle).

Nowadays most general purpose computers are still relying on the key characteristics of this architecture. Within the Von Neumann architecture the processor consists of a control unit, an arithmetic logic unit (ALU) and some key registers used to store numerical values within the processor. These include a Program Counter (PC), an Accumulator, a Current Instruction Register (CIR), a Memory Data Register (MDR) and a Memory Address Register (MAR). These registers are used during the FDE cycle for the processor to fetch instructions and transfer data (between the processor and primary memory) and to execute these instructions.

The rate at which a processor can perform the FDE cycles to process instructions is called the clock speed. For instance, a processing unit with a 3.5GHz clock speed can process 3,500,000,000 instructions per second.

Recent computers have a high clock speed and more advanced processors may also have multiple cores (dual core, quad core etc.) which enable them to process several FDE cycles simultaneously. They may also contain cache within the CPU which can be used to store (and retrieve at a very fast rate) recently or frequently used instructions or data without the need to retrieve these from primary memory. A Central Processing Unit (CPU) with multiple cores, a certain amount of cache and a high clock speed will lead to an increase of the performance of the CPU.

Inside the CPU – Drag and DropOpen in New Window

Poem Decoding Challenge

Posted on December 20, 2023 by Administrator Posted in Computer Science, Cryptography, Python - Advanced, Python Challenges, Solved Challenges

To celebrate the start of the Winter, we have asked our Artificial Intelligence “AI-101” to generate a poem about the cold winter weather. The AI has generated the following poem which consists of a list of numbers! We believe the poem is in a compressed format. We found within the log of the AI a hash table (codebook) as appearing on the tablet below.

We believe this codebook is the key to uncompress the poem. (Click on the picture below to open full screen)

Challenge #1

Use the above codebook and printed poem to reveal the title and 8 verses of this poem.

Challenge #2

Implement a recursive algorithm to uncompress this poem using the given hash table by completing the code below.

Solution...

The solution for this challenge is available to full members!
Find out how to become a member:
➤ Members' Area

Tagged with: recursion

Playing Cards Sorting Algorithm

Posted on December 18, 2023 by Administrator Posted in Computer Science, GCSE Concepts

The aim of this online activity is to sort a set of 8 playing cards randomly picked from a deck of cards based on the following rules:

The cards need to be sorted in ascending order of their values. For the purpose of this task, an Ace will be the lowest value (1) whereas a King will be the highest value (13).
In order reveal a card you need to click on it to flip it. However you will only be able to reveal two cards at a time.
Should you decide to swap two cards, you will need to drag one of the card on top of the other card. Both cards will then swap position.
If you believe a card is in position, you can tick the checkbox underneath it.
If you believe all 8 cards are sorted, you can click on the “Check if cards are sorted” button. If they are in the correct order, from lowest to largest value, all 8 cards will be revealed.
At anytime, you can start this task again with a fresh set of cards by clicking the “New Cards” button.

Your aim is to find a method (algorithm) that works for you and enable you to sort all the cards with a minimum number of swaps.

Playing Cards Sorting ChallengeOpen in New Window

Sorting Algorithms

They are a range of different algorithms that can be used for a computer to sort a list of values. You can investigate some of the most widely used sorting algorithms using the following blog posts:

Logic Gates Circuits used in a Theme Park

Posted on December 11, 2023 by Administrator Posted in Computer Science, Computing Concepts, GCSE Concepts, GCSE Quiz, Solved Challenges

In this set of challenges, you will design and test some logic gates circuits to control different automated systems used to control the following rides of a Theme park:

Ferris Wheel
Drop Tower
Roller Coaster

Ferris WheelDrop TowerRoller Coaster

Ferris Wheel

A Ferris Wheel automated control system controls whether the wheel should be spinning or should be stopped.

The automated system is based on the following inputs:

A main switch is controlled by the main operator to decide if the wheel is in operating (spinning) or not.
- If the switch is on, the wheel is spinning
- If the switch is off, the wheel is not spinning, allowing for passengers to load/unload a cabin.
Weight sensors are also used in each of the cabins of this Ferris wheel. A sensor is “on” if the cabin it’s on is overloaded (too heavy). If any of the sensors is on, the wheel is automatically stopped. For the purpose of this task, we will assume that our Ferris Wheel only contains 4 cabins. We will therefore only use 4 sensors. In reality, more sensors would be needed.

Use our logic gates circuit simulator to design and test a circuit for the Ferris Wheel automated control system. (Click on picture below)

Drop Tower

To join the queue to get on board the Drop Tower, the passengers must comply with some safety rules. A control panel is available to control a gate to let a passenger join the queue. The control panel has 3 switches as follows:

Switch A to indicate whether the passenger is 12 or over.
Switch B to indicate whether the passenger is at least 4-feet tall.
Switch C to indicate whether the passenger is accompanied by an adult.

For the gate to open to let the passenger join the queue for the ride, the rules are as follow:

The passenger must be at least 4-feet tall.
The passenger must either be 12 or over and if not, they must be accompanied by an adult.

Click on the picture below to design and test the logic gates circuit to control the gate, so that if a passenger is allowed to get on board the Drop Tower, the gate is “on”, but if not the gate is “off“.

Roller Coaster

An emergency stopping system controls whether a signal should be sent to the train of a roller coaster to stop it, in case of an emergency. The system is based on the following inputs:

A main switch is controlled by the main operator to start (switch is “on”) or stop (“off”) the roller coaster. There are however only three locations on the track where it is safe for the roller coaster to be stopped.
There are 3 sensors on the track, one on each of these 3 locations. The sensor is “on” if it detects the train at this given location. At least one of the three sensors must be on for the train to be stopped.
A safety guard sensor is also used to detect if any of the safety guards are not securely locked in. When all safety guards are locked in, the sensor is “on”.
If any of the safety guards are unlocked, the sensor is “off”: In this case, the train should automatically be stopped provided that the train is at one of the three safe locations to be stopped.

Use our logic gates circuit simulator to design and test a circuit for the Roller Coaster Emergency Stopping System.

Solution...

The solution for this challenge is available to full members!
Find out how to become a member:
➤ Members' Area

Tagged with: logic gates

Code Maintainability Q&A

Posted on November 30, 2023 by Administrator Posted in Computer Science, GCSE Concepts, GCSE Quiz, Question & Answer, Quizzes

Question 1[4 marks]

The two Python scripts above were created by an IT manager of a school and are performing exactly the same task: to generate a username based on the student’s firstname, lastname and year group. Compare both of these scripts and identify what was done to the code to make it easier to understand, maintain and re-use in future projects?

Question 2[2 marks]

The IT manager would like to make this program more robust by adding a validation check on the year group. The school only has students in year 7 to year 13. How could the IT manager change the code above to make sure the user can only enter a value between 7 and 13 for the year group?

Question 3[4 marks]

The IT manager would like to test his new validation check on the year group. Identify 4 pieces of test data that the IT manager should use to perform a normal/valid test, an invalid test, a boundary test and an erroneous test?

Normal/Valid Test Data:
Invalid Test Data:
Boundary Test Data:
Erroneous Test Data:

The Marauder’s Map Coding Challenges

Posted on November 2, 2023 by Administrator Posted in Algorithms, Algorithms (GCSE), Coding Quiz, Computer Science, GCSE Quiz, Quizzes

Welcome to Hogwarts, school of witchcraft and wizardry! For this set of challenges, you will be helping the famous wizard, Harry Potter, to recover all of his magical possessions.

Effectively, it would seem that a malevolent wizard did cast a spell on Harry Potter’s belongings. As a consequence, twelve of Harry Potter’s favourite magical objects have been buried on the school premises, within or around Hogwarts Castle.

Harry found a note on his bed containing 12 encoded messages that look like some kind of magical algorithms. He believes that he could use Professor Dumbledore’s Marauder’s Map to help him locate his 12 magical objects. However, Harry needs your help to decode these algorithms. Will you be able to use the Marauder’s Map and decode the 12 algorithms to locate all of Harry Potter’s magical artefacts?

The Marauder’s Map Coding ChallengesOpen in New Window
The Marauder’s Map Coding ChallengesOpen in New Window

HTML and CSS Quizzes

Posted on October 16, 2023 by Administrator Posted in A Level Concepts, A Level Quiz, Coding Quiz, Computer Science, HTML, CSS & JavaScript

Do you know your HTML tags used to create a webpage? Do you know how to use CSS to customise the look and feel of all the elements of this page? See how many HTML tags and how many CSS properties you can list in under 5 minutes by completing the following two quizzes.

To learn more about HTML and CSS you can use the tutorials from w3schools:

HTML QuizCSS Quiz

HTML QuizOpen in New Window
HTML QuizOpen in New Window

CSS QuizOpen in New Window
CSS QuizOpen in New Window

Tagged with: CSS, HTML

Standard Deviation Algorithm

Posted on October 13, 2023 by Administrator Posted in Computer Science, Python - Advanced, Python Challenges, Solved Challenges

In statistics, given a set list of numbers, the standard deviation is a measure of the amount of variation or dispersion within the set.

A low standard deviation indicates that the values tend to be close to the mean value of the set.
A high standard deviation indicates that the values are spread out over a wider range.

The formula to calculate the standard deviation for a given set of numbers is as follows:

Where x represents the mean value of the set and n represents the number of values in the set.

Your task is to design an algorithm for a function called standardDeviation() that takes one parameter: a list of integer values. The list can be of any length. Your function will calculate and return the standard deviation for this given list.

Python Code

We have started the code for you by creating a function called inputList() that lets the user input any list of numbers, one number at a time. Your task is now to add the code for the standardDeviation() function.

Test Plan

Test #	Input Values	Expected Output	Actual Output
#1	7,14,9,21,32,15	8.3199893162325
#2	23,101,52,48,107	32.480147782915
#3	10,40	15

Solution...

The solution for this challenge is available to full members!
Find out how to become a member:
➤ Members' Area

Learning Zone ✕

Theory Concepts

Interactive Quizzes

GCSE Computer Science (UK)

A-Level Computer Science (UK)

Coding Challenges ✕

Python Challenges

HTML / CSS & JavaScript

LMC

SQL

Block Programming

Interactive Coding Puzzles

Online Interactive Tools ✕

Coding Tools

Design Tools

Logic Gates Circuits

Cryptography Corner

Member's Area ✕

Register/Sign Up

Get In Touch

Books Corner

Your Task

Challenge #1

Challenge #2

Solution...

Sorting Algorithms

Ferris Wheel

Drop Tower

Roller Coaster

Solution...

Python Challenge

Solution...

Python Code

Test Plan

Solution...

Recent Posts

Our Latest Book