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Learn about sorting algorithms - merge and bubble sort - and searching algorithms - linear and bubble search. Based on the 2020 Eduqas (WJEC) GCSE specification. 8.4: Sorting & Searching Algorithms Exam Board: Eduqas Specification: 2020 Merge Sort Merge sort is a sorting algorithm based on the idea of ‘divide and conquer ’. A merge sort divides a list into half , again and again until each data item is separate . Then the items are combined in the same way as they were divided , but now in the correct order . When the individual lists are all merged together as one list again, then the data is in order and the algorithm will end . Bubble Sort This algorithm is based on the comparison of adjacent data elements . Data elements are swapped if they are not in the correct order . A bubble sort is not suitable for large sets of data. Linear Search A linear search is the most simple search algorithm. Each data item is searched in order from the first value to the last as if they were all laid out in a line . The list does not have to be in any order before it is searched . This search is also known as a sequential search because the list is searched in a sequence from start to end. For large lists , this search is not very efficient . Binary Search A binary search is a much more efficient searching algorithm as it generally searches through fewer data and is often much quicker - especially for large data sets. In a binary search, the middle point of the data is selected with each iteration and many data items can be ignored. However, the list of data must already be sorted in order before a binary search can take place. Q uesto's Q uestions 8.3 - Searching & Sorting Algorithms: Linear Search Explain step-by-step how the number 8 would be found in the following list using a linear search : 12, 5, 3, 2, 8, 19, 14, 6 [4 ] Binary Search Explain step-by-step how the number 2 would be found in the following list using a binary search : 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 [6 ] Merge Sort Explain step-by-step how a merge sort would sort the following list of numbers: 4, 8, 5, 1, 3, 6, 7, 2 [6 ] Bubble Sort Explain step-by-step how a bubble sort would sort the following list of numbers: 3, 2, 6, 4, 1, 4 [6 ] Watch on YouTube Watch on YouTube Watch on YouTube Watch on YouTube 8.3 - Writing Algorithms Theory Topics 8.5 - Validation & Verification

Learn about the purpose, characteristics, advantages, disadvantages, examples and client requirements of application software types, including off-the-shelf, custom off-the-shelf and bespoke software. Resources based on Unit F160 (Fundamentals of Application Development) for the OCR Cambridge Advanced National in Computing (H029 / H129) AAQ (Alternative Academic Qualification). Qualification: Cambridge Advanced National in Computing (AAQ) Unit: F160: Fundamentals of Application Development Certificate: Computing: Application Development (H029 / H129) 1.3.3 - Application Software Types Watch on YouTube : Off-the-Shelf Software Custom Off-the-Shelf Software Bespoke Software There are three application software types you need to know : Off-the-shelf software Custom off-the-shelf software Bespoke software For each software type , you need to know : Its purpose and common characteristics . The advantages and disadvantages of using the software. How client requirements affect the selection of that software. Application Software Types Off-the-Shelf Software Off-the-shelf software is pre-made and available for anyone to buy and use . It is designed for general users and common tasks . It is pre-developed and ready-made with standard features for a wide audience , not custom-built for a specific user. Its purpose is to provide a cost-effective , quick-to-deploy solution for popular applications . Custom Off-the-Shelf Software Custom off-the-shelf software is pre-built like regular off-the-shelf software , but can be slightly customised to meet specific user needs . It offers a balance between quick setup and limited personalisation . It supports configurable features such as add-ons , plugins or modules to extend or adapt functionality while the base software remains maintained and updated by the original developer . Bespoke Software Bespoke software is designed and built specifically for one organisation or user . It fits their exact needs but usually costs more and takes longer to develop . An example is a bespoke system developed for a specific bank with custom software to handle financial regulations , unique products and security needs . Other examples include government systems , hospital patient management and air traffic control . Q uesto's Q uestions 1.3.3 - Application Software Types: 1. Explain the differences in purpose and characteristics between off-the-shelf and custom off-the-shelf software. [4 ] 2. A dental surgery needs new software to manage its customer bookings . Justify which application software type they should use and why . [4 ] 3. Describe two advantages and two disadvantages of the three application software types on this page. [ 12 ] Off-the-shelf software gets its name from the days when software like Microsoft Word was sold on physical discs in shops , for customers to take off the shelf and install at home . D id Y ou K now? 1.3.2 - Software Categories Topic List 2.1 - Software Development Models

Learn about network operating systems, open source operating systems and proprietary operating systems. Resources based on Unit F160 (Fundamentals of Application Development) for the OCR Cambridge Advanced Nationals in Computing (H029 / H129) AAQ (Alternative Academic Qualification). Qualification: Cambridge Advanced National in Computing (AAQ) Unit: F160: Fundamentals of Application Development Certificate: Computing: Application Development (H029 / H129) 1.2 - Operating Systems Watch on YouTube : Network Operating System Open Operating System Proprietary Operating System An operating system is software that manages the resources of a computer system , such as memory , users and files . It also provides a user interface so that humans can interact with the device's hardware . An operating system allows application software to be opened and run . There are three types of operating system that you need to know - network , open and proprietary . Operating Systems Network Operating System (NOS) A network operating system (NOS ) is software that manages network resources and allows computers to communicate over a network . Windows Server , developed by Microsoft , is an example of a network operating system . Characteristics of a Network Operating System Allows for the centralised management of users , data and security across multiple devices on a network . Enables resources such as files , applications and printers to be shared over the network . Manages user authentication and permissions control . Oversees remote access and system monitoring tools . The main type of device that uses a NOS is a server . Other devices, such as desktops or laptops , connect to the server to access shared resources . Windows Server is an example of a popular NOS . Advantages of a Network Operating System Administrators can manage users , files and security on a network from one central location . Resources such as files , printer access and applications can be shared across the network . Access levels can be controlled and user authentication helps protect data . An NOS is scalable - more devices and users can be added as needed . Central servers managed by a NOS make it easier to back up and restore important files . Disadvantages of a Network Operating System Purchasing a NOS and maintaining the servers it runs on can be expensive . Setup and management is complex and may require skilled administrators . If the main server running the NOS fails , connected computers may lose access to resources . Heavy traffic or poor configuration could slow the network down . Who uses a Network Operating System? Application developers can use a NOS to build , test and manage apps that work across networks , such as web applications , multiplayer games or cloud tools . This type of operating system is also used by organisations that need to manage multiple devices , users and resources efficiently across a network , such as a small business or a school . Open Operating System An open operating system is open-source , meaning its source code is freely available for anyone to view , modify and distribute . Source code is the original set of instructions written by a programmer using a high-level language such as Python , Java or C++ . Characteristics of an Open Operating System Users have access to the source code and can see how the OS works . The source code can be modified to suit the specific needs of the user . Development and maintenance may be led by an online community . An open OS is usually free with no licensing costs for most versions. Linux is an example of an open operating system . Android is technically an open-source OS , but most commercial Android devices (like Google Pixel phones ) include proprietary components (like Google Docs or Gmail ), which makes the full system not completely open source . Advantages of an Open Operating System It is usually free to use , modify and distribute the source code . Because the source code can be seen and modified , this type of OS is flexible and customisable . There may be updates from an online community maintaining and improving the software . Promotes experimentation to learn how systems work and try new ideas . Disadvantages of an Open Operating System Programming knowledge and skills are required to modify the source code . There may be security risks if someone edits the source code and redistributes it with malicious code . There will be less official support compared to a proprietary operating system . Some proprietary applications (like Microsoft Access for databases) will only work on a proprietary OS (like Windows ). Who uses an Open Operating System? App developers would use an open OS when the device their application will be used on is not tied to a specific proprietary system (like Windows or MacOS ). For example, a charity making a free educational app for developing countries would choose an open OS so it can run on low-cost , older smartphones . It can be customised and tested on a range of devices . Applications for specific single-purpose systems would also use an open OS , such as an information terminal in a museum . Linux could be used to develop a simple user interface and remove unnecessary features . Proprietary Operating System A proprietary operating system is software that is owned by a company or individual and the source code is not accessible for users to view , modify or distribute . Users must typically buy a licence or agree to the terms of use . Characteristics of a Proprietary Operating System The source code is hidden from the user and cannot be legally modified . A paid licence or subscription is usually required to use the software . It may be maintained and updated by the developer(s) who own it . Only the developer controls updates and the features that are added or fixed . Examples include Microsoft Windows (e.g. Windows 11 ), macOS (for Apple desktops and MacBooks ), iOS (for iPhones ) and iPadOS for iPads ). Advantages of a Proprietary Operating System There is an expectation that it is user-friendly and has been well tested . There may be official support and regular updates for improvements and bug removal . A proprietary OS has a high compatibility with proprietary software such as Microsoft Office or Adobe editing apps . The OS is expected to be stable and secure , with access restricted to system files . Disadvantages of a Proprietary Operating System A paid licence to use the OS is often required , which may be expensive . There is limited customisation for users as the source code cannot be seen or modified . Users rely on the vendor (developer ) for updates and bug fixes . Some proprietary OS are designed to only work on specific hardware (such as iOS only working on iPhones ). Who uses a Proprietary Operating System? App developers will need to use a proprietary OS if they are developing applications for a device that requires a specific proprietary OS , for example if they are creating a game for iPhones , they will need to use iOS . A company designing a finance application on desktops with Microsoft Access and Microsoft Excel must use a proprietary OS like Windows so that it can be integrated with these other types of proprietary applications . Q uesto's Q uestions 1.2 - Operating Systems: 1. What is an operating system ? [2 ] 2. For each of the three types of operating systems , create a poster , information sheet or factfile which includes the following information : Characteristics Advantages Disadvantages Example of how it could be used [10 per OS ] Windows 11 is Microsoft's current operating system . Windows 1.0 was their first release, introduced in 1985 and included basic versions of Calculator , Notepad and Paint . D id Y ou K now? 1.1 - Programs & Applications Topic List 1.3.1 - Application Types

Learn how to create simple programs in Python. Try practice tasks and learn through text and images. Perfect for students learning GCSE Computer Science in UK schools. Formerly pynewbs.com. Follow the instructions in each section and try the practice tasks on every page . At the end of each section are larger problems to solve. Pyt hon Sections 0. Setting up Python Installing and Using Python 1. Printing and Variables a. Printing b. Comments c. Creating Variables d. Using Variables Section 1 Practice Tasks 2. Inputting Data a. Inputting Text b. Inputting Numbers Section 2 Practice Tasks 7. Subroutines a. Procedures b. Functions Section 7 Practice Tasks 8. Lists a. Using Lists b. 2D Lists c. Dictionaries Section 8 Practice Tasks 9. String Handling a. Basic String Handling b. Number Handling Section 9 Practice Tasks 3. Data Types & Calculations a. Data Types b. Simple Calculations Section 3 Practice Tasks 4. Selection a. If Statements b. Mathematical Operators ( & MOD / DIV) c. Logical Operators Section 4 Practice Tasks 5. Importing from Libraries a. Random b. Sleep c. Date & Time d. Colorama e. More Libraries (math) Section 5 Practice Tasks 6. Loops a. For Loops b. While Loops Section 6 Practice Tasks 10. File Handling a. Open & Write to Files b. Read & Search Files c. Remove & Edit Lines Section 10 Practice Tasks 11. User Interfaces a. Graphical User Interface 12. Authentication a. Error Handling Extended Tasks Extended Task 1 (Pork Pies) Extended Task 2 (Lottery) Extended Task 3 (Blackjack) Extended Task 4 (Vet Surgery) Extended Task 5 (Colour Collection) Extended Task 6 (Guess the Word) Extended Task 7 (Guess the Number)

Learn about how to write algorithms, including pseudocode and the different flowchart symbols. Based on the 2020 Eduqas (WJEC) GCSE specification. 8.3: Writing Algorithms Exam Board: Eduqas Specification: 2020 Pseudocode Reminder Generally, pseudocode can be written in any way that is readable and clearly shows its purpose. However, the Eduqas exam board advises that pseudocode for the programming exam should follow the conventions below : Annotation { Write your comment in curly brackets} Define data type price is integer firstname is string Declare a variable's value set price = 100 set firstname = "Marcella" Input / output output "Please enter your first name" input firstname Selection (must have indentation) if firstname = "Steven" then output "Hello" + firstname elif firstname = "Steve" then output "Please use full name" else output "Who are you?" end if Iteration (while loop) while firstname ! = "Steven" output "Guess my name." input firstname repeat Iteration (for loop) for i in range 10 input item next i Define a subroutine Declare Sub1 [Subroutine content indented] End Sub1 Call a subroutine call Sub1 Writing Algorithms In an exam you may be asked to write an algorithm using pseudocode . Previous exams have offered up to 10 marks for a single algorithm . While this may seem daunting, it means you can still gain marks for an incomplete program , so don't leave it blank no matter what! You must decompose the problem and break it down into more manageable chunks . Here's an example question : “A teacher is marking tests. Write an algorithm that allows the teacher to input the number of tests to mark and then the mark of each test. Output the average mark, highest mark and lowest mark. The tests are marked out of 100.” This specific algorithm can be broken down into pre-code and three main parts : Part 0: Declare and assign variables. Part 1: Input the number of tests to mark. Part 2: Input the mark of each test. Part 3: Output the average, lowest and highest marks. Part 0: Variables Read the question carefully and work out the variables you will need in your algorithm. I have highlighted them in blue below: “A teacher is marking tests. Write an algorithm that allows the teacher to input the number of tests to mark and then the mark of each test . Output the average mark , highest mark and lowest mark . The tests are marked out of 100.” There is an additional variable to track as the average mark can only be worked out if we also know the total marks . number_of_tests is integer test_mark is integer average_mark is real highest_mark is integer lowest_mark is integer total is integer number_of_tests = 0 test_mark = 0 average_mark = 0 highest_mark = -1 lowest_mark = 101 total = 0 Before you write the actual program, you must declare the variables you will need and assign values to them. Firstly, declare the data type of each variable . A whole number is an integer and a decimal number is a real . The average must be a real data type because it is the result of division (total ÷ number_of_tests) and could be a decimal number . When assigning values, most numerical variables will be 0 . Most string values would be " " . However this question is a bit more complicated - the highest mark must start as a really low value and the lowest mark must start as a really high value . This is ensure the first mark entered becomes the highest and lowest mark - this will make sense later. Part 1: Input Number of Tests output “Enter the number of tests to mark: ” input number_of_tests After declaring and assigning your variables the next parts will depend on the algorithm you need to write. This example requires the user to input the number of tests . Part 2: Input Each Mark (Loop) for i = 1 to number_of_tests output “Enter the test mark: ” input test_ mark For part 2 we need the teacher to enter each test’s mark . This is best done as a loop as we do not know how many tests the teacher has to mark until they have typed it in (part 1). All code within the loop must be indented . if test_mark > highest_mark then highest_mark = test_mark endif if test_mark < lowest_mark then lowest_mark = test_mark endif We also need to work out what the highest and lowest marks are. This must be done within the loop as the test marks are entered. The test mark is compared to the current highest and lowest marks . If it is higher than the current highest mark it becomes the new highest mark . If it is lower than the current lowest mark it becomes the new lowest mark . This is why we set the highest_mark and lowest_mark to extreme values at the start - so the first mark entered becomes the new highest and lowest . total = total + test_mark next i The final steps of part 2 are to update the total marks and to close the loop . The total is increased by the test mark that has been entered. The ‘next i ’ command states that the current iteration has ended . The indentation has now stopped. Part 3: Outputs average_mark = total / number_of_tests output “The average mark is:” , average_mark output “The highest mark is:” , highest_mark output “The lowest mark is:” , lowest_mark Before the average can be output, it must be calculated by dividing the total by the number of tests . Then the average , highest and lowest marks can be output . Full Answer number_of_tests is integer test_mark is integer average_mark is real highest_mark is integer lowest_mark is integer total is integer number_of_tests = 0 test_mark = 0 average_mark = 0 highest_mark = -1 lowest_mark = 101 total = 0 output “Enter the number of tests to mark: ” input number_of_tests for i = 1 to number_of_tests output “Enter the test mark: ” input test_ mark if test_mark > highest_mark then highest_mark = test_mark endif if test_mark < lowest_mark then lowest_mark = test_mark endif total = total + test_mark next i average_mark = total / number_of_tests output “The average mark is:” , average_mark output “The highest mark is:” , highest_mark output “The lowest mark is:” , lowest_mark This example is slightly more complicated than some of the recent previous exam questions for writing algorithms. Remember to decompose the problem by identifying the variables you need first. Q uesto's Q uestions 8.3 - Writing Algorithms: 1. A violin player performs a piece of music 8 times . They record a score out of 5 how well they think they performed after each attempt. Write an algorithm using pseudocode that allows the violinist to enter the 8 scores and displays the highest score , lowest score and average score . An example score is 3.7. [10 ] 2. A cyclist wants a program to be made that allows them to enter how many laps of a circuit they have made and the time in seconds for each lap . For example they may enter 3 laps, with times of 20.3 , 23.4 and 19.8 seconds . The program should output the quickest lap time , slowest lap time , total amount of time spent cycling and the average lap time . Create an algorithm using pseudocode for this scenario. [10 ] 8.2 - Understanding Algorithms Theory Topics 8.4 - Sorting & Searching

Test your understanding of for loops and while loops in Python. Try practice tasks and learn through text and images. Perfect for students learning GCSE Computer Science in UK schools. top Python - Section 6 Practice Tasks Task One: Odd Numbers Use a for loop to print all odd numbers between 50 and 70 . You will need to use three values in the range brackets, including a step . Requirements for full marks: A comment at the start to explain what a for loop is. Use just two lines of code. Example solution: 51 53 55 57 59 61 63 65 67 69 Task Two: Fish Rhyme Use two separate for loops and some additional print lines to output this nursery rhyme: "1, 2, 3, 4, 5, Once I caught a fish alive, 6, 7, 8, 9, 10 then I let it go again" in the format shown . Requirements for full marks: Two for loops and two additional print lines (6 lines total). Example solution: 1 2 3 4 5 Once I caught a fish alive. 6 7 8 9 10 Then I let it go again. Task Three: Username & Password Create a program using a while loop that keeps asking a user to enter a username and a password until they are both correct . It may be easier to use a while True loop . You will need to use the and command in an if statement within the loop. Requirements for full marks: A comment at the start to explain what a while loop is. Example solution: Enter username: Ben43 Enter password: hamster Incorrect, please try again. Enter username: Ben44 Enter password: ben123 Incorrect, please try again. Enter username: Ben43 Enter password: ben123 Correct Correct login. Welcome Ben43 Task Four: Colour or Number Use a while True loop to let the user enter either A , B or C . A lets them guess a secret colour . B lets them guess a secret number . C breaks the loop , ending the program. Example solution: Enter A to guess a colour, B to guess a number, C to quit: A Guess the colour: green Incorrect! Enter A to guess a colour, B to guess a number, C to quit: A Guess the colour: pink Correct! Enter A to guess a colour, B to guess a number, C to quit: B Guess the number: 4 Incorrect! Enter A to guess a colour, B to guess a number, C to quit: C Quitting program... ⬅ 6b - W hile Loops 7a - Procedures ➡

Learn about six network devices - hub, switch, router, bridge, WAP and NIC. Also, learn about routing tables and cost diagrams. Based on the 2020 Eduqas (WJEC) GCSE specification. 3.4: Network Hardware & Routing Exam Board: Eduqas Specification: 2020 Network Devices Hub A hub receives data packets from a connected device and transfers a copy to all connected nodes . Switch A switch receives data packets , processes them and transfers them on to the device specifically listed in the destination address of the packet. Router Routers are used to transfer data packets between networks . Data is sent from network to network on the internet towards the destination address listed in the data packet. A router stores the address of each computer on the network and uses routing tables to calculate the quickest and shortest path . Bridge A bridge joins together two networks that use the same base protocols . For example, a bridge could link together a LAN to another LAN . Wireless Access Point (WAP) Provides a link between wireless and wired networks . It creates a wireless local area network that allows WiFi enabled devices to connect to a wired network. Network Interface Card (NIC) A Network Interface Card (often shortened to NIC ) is an internal piece of hardware that is required for the computer to connect to a network . It used to be a separate expansion card but now it is commonly built directly into the motherboard (and sometimes known as a network adapter ). Wireless network interface cards ( WNIC ) permit a wireless network connection. Routing A routing table is a list of the optimal routes for data packets to be sent from one device to another. Routing tables should be kept accurate and up to date to ensure that packets are transferred as quickly as possible . During routing the lowest cost route is calculated . This is the shortest path with the fastest nodes to transfer data. Below is a simplified network and basic routing table showing the lowest cost (optimal) route using node A as the source address. Q uesto's Q uestions 3.4 - Network Hardware & Routing: 1a. Describe the difference between a hub and a switch . [ 2 ] 1b. Explain how a modem works. [ 2 ] 1c. Describe the purpose of a router . [ 2 ] 1d. Describe the difference between a gateway and a bridge . [ 2 ] 1e. State what WAP stands for and describe its purpose . [ 2 ] 1f. State what NIC stands for and why it is required . [ 2 ] 2a. Describe what a routing table is and why they should be maintained . [ 2 ] 2b. In terms of routing, what does a low-cost route mean? [ 2 ] 2c. Copy and complete the routing table below using node J as the source address . [ 4 ] 3.3 - Network Topology Theory Topics 3.5 - Protocols

The first part of a quick guide to the basics of Python aimed at Key Stage 3 students. Learn about comments and printing. Python - #2 - Variables 1. Number Variables A variable is a value that can change . Imagine there are 20 biscuits in a jar. Then I eat one. Now there are only 19. You must state what the value of a variable is before it is used . e.g. biscuits = 20 Task 1 - Create a new Python program and save the file as 2-Variables.py Create a variable called sweets and give it the value 15. Then print sweets. Variable names cannot have spaces . You can use underscores if you want, e.g. num_of_eggs When you are printing variables, you don't put them in speech marks . Otherwise, it will print the variable name and not the value. 2. String Variables A string is a programming term for a collection of characters . When you are giving a variable a string value, it must be written in speech marks . Remember when you print the variable however, it is never printed in speech marks . Task 2 - Create a variable called name and give it the value of your name. Then print the name variable. 3. Using Variables in a Sentence When we have printed the variables so far, they have not been very informative! You can print variables together with sentences so that they mean more. Use a comma ( , ) between variables and sentences . Task 3 - Use the pictures to help you add commas and sentences to your program to be more informative. 4. Using Variables Together You can print more than one variable together in the same sentence by separating them with sentences and commas . If this doesn't work, double-check your program has a comma between each variable and sentence . Task 4 - Type a new print line that uses both your name and your sweets variables together. Use the image to help you. Challenge Programs Use everything that you have learned on this page to help you create these programs... Challenge Task 1 - Funny Animals Create a new Python program. Save it as ' 2-FunnyAnimals.py ' Add a comment at the top with your name and the date. Create a variable for a colour and give it a value (e.g. "blue") Create a variable for an animal and give it a value (e.g. "horse") Print a funny sentence that uses both variables. BONUS : Try to use only one print line. BONUS : Try to use only three lines in total . Remember: Break up variables in a print line by using commas. When you run it, it could look something like this: Challenge Task 2 - Funny Sentence Create a new Python program. Save is as ' 2-FunnySentence.py ' Add a comment at the top with your name and the date. Write a program that uses three variables, an adjective (descriptive word), a number and an animal. Print a funny response using all variables. BONUS : Try to use only one print line. BONUS : Try to use only four lines in total . Remember: Break up variables in a print line by using commas. When you run it, it could look something like this: <<< #1 The Basics #3 Inputs >>>

A list of programming topics including HTML, Greenfoot, Python. All Programming Topics Python HTML Greenfoot Assembly Language App Inventor 2

The most common errors made in Grennfoot when making a game and how to fix them, including when missing punctuation is expected or the end of file is reached while parsing. Common Greenfoot Errors Greenfoot Home If the world becomes greyed out and you can't click on anything then an error has occurred. The actor with the error will have red lines on it. When an error occurs, a red squiggly line will appear underneath the problem. Hover your mouse over the line and a helpful message will appear to help you solve the issue. Some of the more common errors (and how to fix them) are listed below: ; expected Every line with a white background must end in a semi colon ( ; ) ) expected You have missed a bracket . Count the number of open brackets and the number of closed brackets on a line and make sure you have an equal number of both. reached end of file while parsing You are missing at least one curly bracket ( } ) at the end of your program . Press enter to move onto a new line at the bottom; you must have a closed curly bracket with a yellow background and another closed curly bracket with a green background . cannot find symbol You have typed a command incorrectly . Greenfoot uses a system where commands have no spaces and each word after the first word is uppercase . Such as isKeyDown not IsKeyDown and not isKeydown. Check your spelling and capitals carefully. Stuck ? If you start typing but can't remember what commands come next, press Ctrl and Space together to show a list of all possible commands that you can use.

Learn about algorithms including pseudocode and flowcharts. Based on the 2020 Eduqas (WJEC) GCSE specification. 8.2: Understanding Algorithms Exam Board: Eduqas Specification: 2020 What is an algorithm? An algorithm is a set of instructions , presented in a logical sequence . In an exam you may be asked to read and understand an algorithm that has been written. To prove your understanding you may be asked to respond by actions such as listing the outputs of the algorithm, correcting errors or identifying an error within it. Programmers create algorithm designs as a method of planning a program before writing any code. This helps them to consider the potential problems of the program and makes it easier to start creating source code. There are two main methods of defining algorithms : Defining Algorithms - Pseudocode & Flowcharts Pseudocode Pseudocode is not a specific programming language but a more general method of describing instructions . It should be unambiguous, and it should not resemble any particular kind of programming language (e.g. Python or Java), so it can theoretically be turned into working code in any language. Generally, pseudocode can be written in any way that is readable and clearly shows its purpose. However, the Eduqas exam board advises that pseudocode for the programming exam should follow the conventions below : Annotation { Write your comment in curly brackets} Define data type price is integer firstname is string Declare a variable's value set price = 100 set firstname = "Marcella" Input / output output "Please enter your first name" input firstname Selection (must have indentation) if firstname = "Steven" then output "Hello" + firstname elif firstname = "Steve" then output "Please use full name" else output "Who are you?" end if Iteration (while loop) while firstname ! = "Steven" output "Guess my name." input firstname repeat Iteration (for loop) for i in range 10 input item next i Define a subroutine Declare Sub1 [Subroutine content indented] End Sub1 Call a subroutine call Sub1 Flowcharts A flowchart can be used to visually represent an algorithm. The flowchart symbols are: Algorithm Examples Below are two different methods for representing the same algorithm - a program to encourage people to buy items cheaply at a supermarket. The program allows the price of items in a supermarket to be entered until the total reaches 100. The total price and the number of items entered are tracked as the program loops. Once the total reaches 100 or more, an if statement checks how many items have been entered and a different message is printed if there are 20 or more items, 30 or more items or less than 20 items. Pseudocode Flowchart {This is a program to see how many items you can buy in a supermarket before you spend over £100} total is integer, itemsentered is integer, itemprice is integer set total = 0 set itemsentered = 0 while total < 100 output "enter the price of the next item" input itemprice total = total + itemprice itemsentered = itemsentered + 1 repeat if itemsentered >= 20 then output "You are on your way to saving money." elif itemsentered => 30 then output "You're a real money saver." else output "Look for better deals next time." end if Reading Algorithms In an exam you may be asked to read an algorithm and prove your understanding , most commonly by listing the outputs . Start from the first line and follow the program line by line , recording the value of variables as you go . When you encounter a for loop , repeat the indented code as many times as stated in the range . Example Algorithm: Start NewProgram i is integer maxvalue is integer input maxvalue for i = 1 to maxvalue output (i * i) ??????? output 'program finished' End NewProgram Example Questions: 1. List the outputs produced by the algorithm if the 'maxvalue' input is 5 . 2. State the code that has been replaced by '???????' and what the code's purpose is. Example Answers: 1. Outputs: 1 4 9 16 25 program finished 2. Missing Code: next i Purpose: Moves the loop to the next iteration. Watch on YouTube Q uesto's Q uestions 8.2 - Understanding Algorithms: 1a. Read the algorithm shown on the left and list all outputs in the correct order if the inputs are 2 for height and 72 for weight . 1b. Give the code that is missing from line 25 . 8.1 - Programming Principles Theory Topics 8.3 - Writing Algorithms

The first part of a quick guide to the basics of Python aimed at Key Stage 3 students. Learn about comments and printing. Python - #1 - The Basics 1. Start with Commenting Programmers write A LOT of code. They need to understand exactly what they have written, especially if they are working as part of a team or returning to code after working on other projects. To help them understand what they have written, programmers use comments to annotate (explain) their code . Task 1 - Create a new Python program and use # to write a comment that says your name and the date. Save the file as 1-Basics.py In Python, type the # symbol then your message to write a comment. Comments are not printed when you run a program! It is a good idea to start every program with a comment, so you know what the program is about . 2. Printing to the Screen The most basic and common command you will use in Python is print . Inside the print brackets, you can write a message within speech marks . Your print command should turn purple - don't use any capital letters in Python unless it is inside speech marks! Task 2 - Write a nice message by using the print command, brackets and speech marks. Press F5 to run your program. 3. More Printing You can write multiple print lines one after another to print on different lines. Task 3 - Add two more print lines to your program. You can choose any message that you like. 4. New Lines You can use the special command \n to start a new line . This allows you to write on multiple lines but only use one print line. Use the backslash ( \ ) not the forward-slash ( / ). Task 4 - Use \n to write a 3 sentence conversation in only one line of code. Challenge Programs Use everything that you have learned on this page to help you create these programs... Challenge Task 1 - Days of the Week Create a new Python program. Save it as ' 1-Week.py ' Add a comment at the top with your name and the date. Create a program that prints the days of the week, with each day on a new line. BONUS : Try to use only one print line. BONUS : Have no empty spaces at the start of each line. When you run it, it should look like this: Challenge Task 2 - Conversation Create a new Python program. Save it as ' 1-Conversation.py ' Add a comment at the top with your name and the date. Create a program that prints a 6-line conversation between two people. It is up to you what these two people are talking about. BONUS : Try to use only one print line. BONUS : Have no empty spaces at the start of each line. When you run it, it could look something like this: #2 Variables >>>