Introduction to Computer Science

Computing Study Guide

• The purpose of the guide is to make the user understand the key areas of computer science.

Key Areas of Computer Science

• Programming involves the design and creation of computer programs using text-based languages such as Python.
• Managing data involves the storing, organizing, and managing data using databases and spreadsheets to support problem-solving.
• Computational thinking involves using computing to explore and analyze data and developing skills to support problem-solving.
• Digital communication involves transferring digital data between computing devices securely and accurately.
• Computer systems involves understanding how computer hardware and software work together to solve problems.

Key Concepts

• Network design is a Key Concept.
• Algorithms and sub-routines are Key Concepts.
• Sub-routine: A standalone section of code that can be called from the main program.
• Machine learning and Industry 4.0 are Key Concepts.
• Industry 4.0 refers to how industry combines electronics with new technologies like machine learning, artificial intelligence, robotics, and green energy.
• One-dimensional arrays and string manipulation are Key Concepts.
• String manipulation is the process of changing the format of a variable/string to allow it to be analyzed.
• Databases, spreadsheets, and Big Data are Key Concepts.
• Big Data: Datasets that are too large or complex for traditional data-processing applications like databases or spreadsheets.
• Software prototype development is a Key Concept.
• Prototype: An initial product created for testing and reviewing before a final product is released.
• Fetch-decode-execute cycle: Understanding how program instructions are stored and run one at a time.
• Language translators are needed to ensure the processor can understand program instructions.

Presenting Choices: Combining Constructs - Objectives

• Use Python to understand count-controlled loops and arrays.
• Plan an algorithm and program to act as a chatbot.

Presenting Choices: Combining Constructs - Key Skills

• Following and editing algorithms in pseudocode or flowcharts are key skills.
• Creating algorithms using flowcharts and pseudocode are are key skills.
• Using and explaining iteration statements with count-controlled loops are key skills.
• Predicting algorithm outcomes using iteration is a key skill.
• Comparing algorithms for the same solution and deciding which is best is a key skill.
• Creating algorithms using sequence, selection, and count-controlled iteration is a key skill.
• Identifying and explaining one-dimensional arrays is a key skill.
• Identifying and describing data types in Python programs (integer, real, character, string, Boolean) are key skills.
• Developing Python programs with count-controlled loops is a key skill.
• Accessing data from an array using Python is a key skill.
• Developing Python programs using string manipulation (length, uppercase, lowercase) is a key skill.
• Using iterative development on Python prototypes is a key skill.
• Developing and applying test plans with normal, extreme, and invalid data are key skills.
• Identifying and describing syntax, logic, and runtime errors are key skills.
• Using trace tables to debug errors in Python programs is a key skill.

Warm Up

• Create a flowchart to make a decision, like choosing a pizza topping.

Scenario

• Create a chatbot program to interact with students during the selection of options or subject areas to continue studying.
• The chatbot will ask a series of questions, store answers, and help make a final decision.

Chatbots

• Chatbots are software applications that carry out online conversations with users, helping to identify solutions through questioning.
• Chatbot: A software application that uses text to ask questions to help a user.
• They can be used on websites to answer queries without human involvement.
• Spotify uses a chatbot to allow users to search for, listen to, and share music.

Get Started

• Try the "20 Questions" game to understand how questions help narrow down choices.

Key Points

• Each question in a flowchart helps narrow down options.
• Questions lead from one another in a sequence, with "Yes" or "No" answers.
• Technology can support customers through questioning via chatbots.

Before Starting - You should be able to:

• Develop a Python program using an iterative process.
• Follow and understand algorithms in pseudocode.
• Explain and use AND, OR, and NOT logic within an algorithm.
• Follow flowcharts and pseudocode algorithms with conditional statements.
• Predict algorithm outcomes.
• Create Python programs with conditional statements and different data types.
• Decompose problems into smaller sub-problems.
• Develop and apply test plans.

Did you know?

• Chatbots are useful for growing businesses to meet customer demands.
• They filter calls that need to be answered by a person.

Rule-Based Chatbots

• Have predefined questions.
• Examples: IT first-line support, health chatbots.

Chatbots with Artificial Intelligence (AI)

• Offer intelligent conversations as Al learns from selections and answers.
• Utilize machine learning.
• Machine learning: Ability of a computer system to learn over time.

Two Main Types of Chatbots

• Rule-based chatbots
• Chatbots with artificial intelligence

Data Types and Collecting Variable Data

• Consider the data type when planning an algorithm.
• Data type: A classification applied to a data item specifying which type of data that item represents.

Data types

• String: A series of characters surrounded by quotation marks.
• Character: A single letter, digit, or symbol (not used in Python).
• Integer: A whole number.
• Real (float): A decimal number.
• Boolean: True or False.
• Python assumes input is a string unless told otherwise.
• To add values together, use int to store input as an integer.

Key Definitions

• Algorithm: Step-by-step instructions to solve a particular problem.
• String: Sequence of characters that can be text, numbers, or symbols; quotation marks around the characters define it as a string.
• Character: Single letter, digit, or symbol.
• Integer: Whole number.
• Real: Also known as a float; a decimal number.
• Float: Decimal number.
• Concatenation: Joining two strings together.
• Cast: Change the data type of a variable.

Planning Variables

• For a chatbot asking about free hours, favorite activity, and activity time:
  • Variable name hours : Data type Integer.
  • Variable name activity : Data type String.
  • Variable name activity Time : Data type Real.
  • Variable name timeLeft : Data type Real.

Planning and Testing Algorithms

• Before diving into coding, it's helpful to plan out your variables and their data types, making the coding process smoother.

Variable Usage

• hours is set as an integer.
• activityTime is a float (real number).
• activity defaults to a string.
• Data types aren't shown in pseudocode, so a table can help.
• It's important to name variables in a way that clearly indicates what they store. Two main naming conventions are:
  • camelCase: Start with lowercase, and capitalize the first letter of each subsequent word (e.g., camelCase).
  • snake_case: Use lowercase and replace spaces with underscores (e.g., snake_case).

Test Plans

• A test plan is a document detailing the tests to be carried out when a program is complete, indicating whether they are successful or not.
• The image shows a detailed process of developing and testing a Python program, emphasizing iterative steps and decision-making based on user input and conditions.
• The flowchart is critical for planning the tests.

Iterative Development

• The development of a program is an iterative process, where the initial idea evolves through development, prototyping, and adjustments.
• Iterative means to repeat development steps until the prototype is ready for release.
• Program code can be broken down into smaller sections, developed, tested, and reviewed before adding the next section.
• Developing a chatbot program starts with pseudocode.
• Developments can be considered as the programmer starts to write the code.

Trace Tables

• A trace table is a technique for predicting step by step what will happen as each line of an algorithm or program is run, and to identify errors.
• A variable is a temporary storage location in memory whose contents can be called and edited at any time in the program.
• The contents of each variable can be mapped out in a trace table to show where they change as a program runs. Trace tables are structured like test plans.

Trace Table Elements

• Line: The line in the pseudocode algorithm or the step in the flowchart.
• Variable: The name of the variable, with its value noted each time it changes.
• Condition: The conditional statement being checked (True or False).
• Output: The value stored in a variable.

Error Processing

• Errors can be categorized in three ways:
  • Syntax errors: Errors in the program code that stop the program from running (e.g., missing brackets or incorrect spelling).
  • Runtime errors: Errors that occur while the program is running because the instructions cannot be completed (e.g., incorrect variable name).
  • Logic errors: Errors that allow a program to run but not output what is expected (e.g., incorrect conditional operator).
• Testing an algorithm before it is developed into program code can help find and fix errors early on.

Conditional Operators

• == equal to
• != not equal to
• > greater than
• >= greater than or equal to
• < less than
• <= less than or equal to

Identifying Logic Errors

• If an error isn't caught early, an incorrect operator in the program code might go unnoticed until later in the process.
• When a score of 90 is entered, the student isn't receiving the expected "Distinction" level. This is because the conditional operator is set as > (greater than) instead of >= (greater than or equal to).

Programming Constructs: Sequence, Selection, and Iteration

• Sequence is the order in which program code needs to be to work correctly.
• Selection adds choices to a program using if, elif, and else statements, so the next instruction is decided by a condition's outcome.
• Iteration is repeating a series of steps to continuously develop a program until the final solution is reached; a set of instructions that are repeated, also known as a loop.

Count-Controlled Loops (For Loops)

• A count-controlled loop repeats a series of program instructions a set number of times. This type of loop is also called a for loop.

For Loop Elements

• for tells the computer that it will run a for loop.
• i is a variable that counts how many times the code in the loop has been repeated, starting at 0 and increasing by 1 each time the loop finishes running.
• in separates the variable from the number of times the loop will run.
• range(5) defines the number of times the loop will run.
• : signals the beginning of the code that will be repeated.
• print("This is loop,", i) will output the text "This is loop," followed by the value stored in the variable i to show the iteration that the program is on.

Structure of a For Loop

• All lines of code that need to be repeated when the loop runs are indented underneath, in the same way that code is indented after if, elif, and else.
• The structure of a for loop is important.

Practical Application: Chatbots and Loops

• A chatbot might need to ask the same set of questions multiple times. Use a for loop to set the number of times a question is asked and test the input using selection.
• Conditional statements should be indented inside the for loop.

Key Points for Loops

• A loop helps prevent rewriting lines of program code multiple times.
• Efficiency of a program is measured by how long it takes to run.
• Shorter code is more efficient.

Iteration in Algorithms

• Flowcharts for comparisons can be used to identify similarities and differences.
• In flowchart 2, use of a loop makes the algorithm more efficient.
• "The efficiency of a program is measured by how long it takes to run. Usually, if the code can be written in fewer lines, it is more efficient."
• Program code is written using three lines of code.
• By using a for loop, the code would require six lines of code. Therefore, the program with the count-controlled loop is more efficient.

For Loop in Pseudocode

• The for loop in pseudocode is defined using the starting value of the variable and the value that it needs to count to.
• The for loop is shown using ENDFOR.

Countdown Algorithm Comparison

• The efficiency of a program is measured by how quickly it runs.

Iterations and Arrays

• A for loop was used to output the same question three times, reducing the amount of code needed. This doesn't store all three answers in separate variables. Instead, each input from the user overwrites the content of the variable favSubject.
• Array: A data structure that can store more than one item of data under a single identifier.
• Arrays are called lists and can include items of any data type.

More on Arrays

• A Python list is defined similarly to a variable: list name, equals sign (=), and square brackets ([]) to show the start and end of the data items
• Items in the list are separated by commas.
• The list prints on one line, including the square brackets and quotation marks.
• the len() function can be used to find out how many items are in a list.

shoppingList = ["bread", "milk", "apples"]
num = len (shoppingList)
print ("There are",num, "items in the list.")

• use the append() method is used to add an item to the end of a list.

Applying Arrays to Chatbots

• An empty list called favSubjects can be set up at the start of the program.

favSubjects = []

• In the program's new version it now makes use of an array and two Python loops so it can accept inputs, store the information in the array and eventually display what the user entered.
• The updated program will now use a second for loop to print out the subjects

Additional Array methods

• append()
• for in
  • print()

Data Lists and Structures

• Data Item: A piece of information that represents part of the data that makes up a person, place, or thing
• List: A data structure that stores multiple items of data in a single variable; the values can be changed.

Developing Chatbots Further

• Choose the input that will determine the next step
• Algorithm should be planned with flowcharts and pseudocode.

Additional Information in the Examples

• The program asks the user whether they prefer watersports or team games.
• It then saves their choice in typeOfActivity.
• If type0fActivity = "W"-the chatbot shows a list of water activities stored in an array. The program outputs a question asking the user to select which water activity they like. and then saves their choice in activity1 & confirms their choice.
• The chatbot displays a list of team and outputs questions that make the user assign preferences in outputs from activity2

Algorithm Development

• If the program is developed to ask users to choose between three types of activities, then an additional comparison is needed and elif is added

Testing and Errors

• Each type of Error impacts coding
• Syntax Error: An error in the program code disrupts the code from running
• Syntax Error: Results from missing brackets, a missing colon, or missing indentation
• Runtime error: The error of running a program in python cannot execute
• Logic Error: The program is allowed to run, but gives unexpected results/output

Data types for Error Testing

• Normal Test Data: Data correct to be accepted by a program.
• Extreme Test Data: Acceptable data at the ends of the possible data range, still valid because within parameters.
• Invalid Test Data: Data that is to be rejecxted by a program and can be invalid.

String Manipulation

• Adjustments can be made with code to adjust:
  • convert the whole input to lowercase letters .lower()
  • Convert input to uppercase letters using .upper()
  • Convert 1st part to uppercase/rest string to lowercase via .capitalize()
  • Output the length of characters stored using - len(activity)

activity = input ("Enter a possible activity: ").capitalize()
activity = ["swimming", "running", "walking"]
print (len (activity))

• String Manipulation: The format of strings allow it to be analyzed.

Loops & ARrays

• 2 Empty arrays are in place to start the program
• The program asks the user three times to enter a friend's name and Subject
• Each name is stored in the array "names" and subject stored in another array"favSubjects"
• The Program uses zip() to iterate through both arrays simultaneously.

names = []
favSubjects = []
for i in range(3):
name = input("Enter your friend's name: ")
names.append(name)
subject = input("Enter their favorite subject: ")
favSubjects.append(subject)
print("Your friend's details are:")
print("-----------------")
for name, subject in zip(names, favSubjects):
print(name, "likes", subject)

Microbit

• Errors can show a sad face or an icon

MicroBit components include:

• Display (25 individual LED lights)
• Buzzer (located on the reverse)
• General-purpose input/output (GPIO) pins

Coding the MicroBit

• A microbit is directly programmed through specific websites.

Coding steps include:

• Use conditional Operators
• Program it into the MicroBit
• Sequence
• Test plan with data inputs
• List & inputs
• Random guesses & Play Tunes
• New Images
• arrays, loops,
• new functions
• Game play and set

Game code Includes:

• a keyboard and external physical device to trigger answers
• answer should determine to a yes or no to "trigger another subject"

Testing Requirements:

• Random Set from data
• The accelerometer or button should represent when the player makes an assumption or answers a tune

Terminology and sensors

• Cables For creating temporary electrical connections between devices
• the code error shows the process is in stop running mode
• General-purpose (GPIO): Microbit's that have inputs and outputs
• (GPIO): the devices are then connected to the microbit by crocodile clips.
• syntax rules in computer
• hardware systems are used to operate the computer
• Microprocessors and code read information to tell the bit what to do
• text-based commands: uses written codes in the specific code

Accelerometer

• The microbit detects changes in direction through the tests with quotations. It gathers data

Pseudocode and Code

• "Use" START, STOP to show steps as a reminder
• if functions are not completed the output will be a crash
• The goal is to minimize code to reduce load

Micro Python

• from microbit import *
• allows checks from the start from input

Additional steps in coding

• The conditional statement. (if) is run the process should go and is needed
• sleep() determines if the image should show for 2 seconds.

Data Check

• Completes a check if the criteria is true

Steps to Test and set up Code

• make a "test plan" file to document and organize tests
• set up files and identify variables to access

Setting Code variables and constants.

• Code Types
• normal types should data correct for a program
• Exttreme Data should be the data that reaches the limit parameter given
  • Invalid - Rejected
• The Code to be ran

MicroBit Specific Data Code

• data or a data process includes certain instructions to ensure code can function. randint - generates random numbers
• Camelcase : Lowercase, and uppercase the first code
• Cammel code no spaces

code instructions

• "count-Controlled Loops" is the code needed to have the sequence code have repeatable turns

loop codes:

• "For" functions to turn the code certain times a certain loop or number of times is preformed.

terms of processer

- the code must be read from top to bottom in sequential order
- The  ALU must do every process one step by one process.

Tracing

  the process that tracks algorithms one step at a time in lines of process

Steps for data types to avoid crashing:

• IMPORT library
• random = 0 ( or any starting number)
• IF microbit numbers code runs - OUTPUT / display code

Terms for code and hardware:

coding:

• variable = memory that keeps one type assigned -arrays = has mixed groups & data (numbers, characters or text )

The world of networks

Steps of devices communicating and communicating

•

• Devices check connections to a network. •The types use addresses for device networks.

NetWork definitions for Data:

• Collection: devices either connected by wire or wirelessly • Raw data and figures • The data for how a small unit of information packaged through a network. sustainably to build the network for maintenance. • fit For purpose for something specific to its use. • Network topology; shows a diagram of how networks work through hardware. • Interference; is noise disrupts that sends transmissions. • bandwidth has heavy data through communication. • internet: To connect devices to the internet • Personal area (short term) in a short area only 10 meters • wider areas connect to regions. • local area (small) such as home/school use. • the isp that connects devices and use • power: connects to services such as data management with file servers. • Access: to access the network. ( wireless) • physical parts that connect • connects to a router through • mac: program card programmed to access devices/find them.

Network security

• Restricts devices to one network • allows users access to files • monitors the data for a secure transmission

Network Topologies

• a network in Devices are connected via the main cable for the area.

• Terminator allows it to be received as if something were to stop Colliding: when bumps and errors occur.
• Star Network In a central switch, each device is connected. Ringing when devices connect to a network in a ring.

Steps of connecting

• Tranport Control in TCP/IP protocol. has packets and addresses devices and delivers.

Networks also use:

• http/https:to access a data base with info on the web that is secure.

More Considerations

• Scalability factors such as stability/data loads

In general: Systems need to be secured, managed and stable.

Additional software

-online-storage: internet has space to download - removable storage such as a hard disk drives: storing data -cload computing use for software on the internet - the organisation is used to reorginize files

• use software for the computer that's stored
  • Use remote - data to connect to computers

Network Protection

• security is kept to ensure safety to the computer by malware and spyware.

terms

• Virus scanning: to know about viruses quickly • The computer then makes a file • encryption converts files to data to not be intercepted • set security, etc set in a automated function for security

Errors and more types of processes

parity-checking: ensure the data will match the process from The hardware. To prevent data will have a physical part. Check. Parity can occur one way or horizontal.

more checks

Check what data will be good to pass tests set a range of data will all requirements for

The set up

Follow the program instructions set data to look through systems. • use a system with one of • the steps in security

In General

1. all data with structures and values.
2. a computer with a set amount of 3 .set the code and system for use and follow

final projects will have networking skills.

• explain what has been done.

Software is:

The instructions tell code how to run through the device.

The code processes

allows users who know how to use it to control The hardware can be managed and operated as well.

The program or device has aspects that follow a process to execute the main command. The program has access that includes the central part unit CPU

Computer Organization

•The operating system is the program that can run The computer hardware •The operating system provides interface and is an interface for applications.

terms

• The programs in order • facts that can figure is The systems system how to grow in process •. Processor. And more the code follows

• how the system has a good user

• the system needs well tasks managed as an os can follow

• examples of systems to use

• translator is used

• What is more to run to improve

• What you can convert with the storage data

• The circle is to be coded one at a time

• for what and what to include how machine can be used

• describe how the systems are good to implement

How processes access with hardware

To transfer the data it can be done for each transfer bit how computers can receive. • can be easy or be hard -. Transistors what it can

The Code process

• The bit has to be

• The bytes how to get to data one step at a time
• transfer to understand process with

terms of hardware:

• A low to easy level of communication is can transfer and manage
• An assembly the code is symbol the process can transfer with

the high level that can process codes

• all types of software to have code. what to do in the software so as the

the program has to do 1 step at a time

• for each hardware components

instruction access

can read with codes. to test code for example

• num = num1 + num2 transfers 3 loads through

Terms

• Unit - the load of the code and processes
• memory- the stack load can read data The instruction from the process. the core process

the data cycles:

• a machine has a set combination codes is done with chips