Computing Terminology

Posted on November 24, 2015 by Administrator Posted in A Level Concepts, A Level Quiz, Computer Science, Computing Concepts, Computing Terminology Quiz, GCSE Concepts, GCSE Quiz, Quizzes

Check your computing terminology by joining the dominoes below: (Click on picture to start).

Computing TerminologyOpen Domino Activity

Yes or No!

Posted on November 20, 2015 by Administrator Posted in Computer Science, Python - Intermediate, Python Challenges

Learning Objectives

When your computer prorgam is asking questions to the end-user, the end-user may not answer these questions the way you expected them to. This may cause your program to not work properly. Ideally a good program should use some form of validation checks to ensure that the user is providing their answers in the correct format.

Let’s look at the following code that asks a simple Yes/No question:

answer = input("Are you over 16?")
if answer == "Yes":
   print("You can take driving lessons to prepare for your driving test.")
elif answer == "No":
   print("You are too young to learn how to drive a car.")

What would happen if:

The user answers Yes ?
The user answers No ?
The user answers YES ?
The user answers no ?
The user answers Not yet ?

Now let’s look at how we could improve this code further:

Solution #1Explanations

answer = input("Are you over 16?").upper()
if answer == "YES":
   print("You can take driving lessons to prepare for your driving test.")
elif answer == "NO":
   print("You are too young to learn how to drive a car.")

Check the code, did you notice that we added .upper() at the end of line 1?
This will convert the user input into capital letters.
Then, within our if statements, we can compare the user input with “YES” and with “NO”.

What do you think will now happen if:

The user answers Yes ?
The user answers No ?
The user answers YES ?
The user answers no ?
The user answers Not yet ?

Solution #2Explanations

answer = input("Are you over 16?").upper()
if answer == "YES":
   print("You can take driving lessons to prepare for your driving test.")
elif answer == "NO":
   print("You are too young to learn how to drive a car.")
else:
   print("Sorry your answer is not recognised. Restart the program and make sure you answer with the word Yes or the word No.")

By adding an else statement we can give some feedback to the end-user to tell them why their answer is not valid and how they need to answer the question next time

What do you think will now happen if:

The user answers Yes ?
The user answers No ?
The user answers YES ?
The user answers no ?
The user answers Not yet ?

Solution #3Explanations

answer = ""
while (answer!="YES" and answer!="NO"):
  answer = input("Are you over 16? (Yes or No)").upper()

if answer == "YES":
  print("You can take driving lessons to prepare for your driving test.")
elif answer == "NO":
    print("You are too young to learn how to drive a car.")

Using a while loop, we keep asking the question up until the user has typed a valid answer (Yes or No).
What do you think will now happen if:

The user answers Yes ?
The user answers No ?
The user answers YES ?
The user answers no ?
The user answers Not yet ?

Solution #4Explanations

def askYesNoQuestion(question):
  YesNoAnswer = ""
  while (YesNoAnswer!="YES" and YesNoAnswer!="NO"):
    YesNoAnswer = input(question).upper()
  return YesNoAnswer

answer = askYesNoQuestion("Are you over 16? (Yes or No)")
if answer == "YES":
  print("You can take driving lessons to prepare for your driving test.")
elif answer == "NO":
    print("You are too young to learn how to drive a car.")

By creating our own askYesNoQuestion() function we can easily reuse this function every time we want to ask a YesNo question! In our main program, it is as easy as using an input command. It is however a lot more effective because it makes sure the user gives a valid answer!

Solution #5Explanations

def askYesNoQuestion(question):
  YesNoAnswer = input(question).upper()
  if YesNoAnswer == "YES" or YesNoAnswer == "NO":
     return YesNoAnswer  
  else:
     return askYesNoQuestion(question)

answer = askYesNoQuestion("Are you over 16? (Yes or No)")
if answer == "YES":
  print("You can take driving lessons to prepare for your driving test.")
elif answer == "NO":
    print("You are too young to learn how to drive a car.")

This time our askYesNoQuestion() function is not using a while loop but it is using recursion: It’s calling itself. Check on line 6 for the recursive call to itself. And it will keed doing so until it receives a valid answer.

Extension Task:

These different approaches to validate a user input only work for “Yes” / “No” questions.
Would you be able to adapt these to make them work for:

Multiple answers questions? e.g. Which Science subject do you prefer: Biology, Physics, Chemistry or Computer Science?
Number based questions? e.g. Which year group are you in: Only accept a value between 1 and 13. (Tip you will need to use < and > comparison operators to validate the user input.)

Tagged with: iteration, Selection, String Manipulation, Validation

Flags of the World

Posted on November 18, 2015 by Administrator Posted in Computer Science, Computing Concepts, GCSE Concepts

We are trying to build a program that will ask the end-user to choose a flag amongst six flags. The program will then try to guess the selected flag by asking a maximum of two questions.

Look at the flowchart below used to describe our algorithm: (Click on flowchart to open in new window)

Challenge #1

Analysing this flowchart, can you guess the country corresponding to these six flags? (Type your answer below each flag).

Challenge #2

Using Flowchart Studio, design a similar flowchart used for the computer the guess the correct flag amonst these six new flags. You will need to ask different questions.

Challenge #3

Can you tweak the algorithm from the previous task to get the computer to guess the correct flag amongst all twelve flags, using a maximum of three consecutive questions?

Tagged with: Flowchart, Selection

My daily routine

Posted on November 13, 2015 by Administrator Posted in Computer Science, Python - Beginner, Python Challenges

Learning Objectives

When you write lines of code, there are three ways you can control the order these lines will be executed by the computer:

Sequencing: This means that the computer will run your code in order, one line at a time from the top to the bottom of your program. It will start at line 1, then execute line 2 then line 3 and so on till it reaches the last line of your program.

Selection: Sometimes you only want some lines of code to be run only if a condition is met, otherwise you want the computer to ignore these lines and jump over them. This is achieved using IF statements. e.g. If a condition is met then lines 4, 5, 6 are executed otherwise the computer jumps to line 7 without even looking at line 4,5 and 6.

Iteration: Sometimes you want the computer to execute the same lines of code several times. This is done using a loop. There are three types of loops: For loops, while loops and repeat until loops. That’s handy as it enables you not to have to copy the same lines of code many times.

Let’s Get Coding

For this task we are going to write a program that uses sequencing, selection and iteration all in the same program! Our program will be used to print our daily routines on screen over a full week. Look at the code below and try to make sense of how it works. Can you spot where and how sequencing, iteration and selection are used in this code?

Your Task

Your task is to tweak this code to customise your daily routines. Add to it some of the activities or clubs you go to. For instance:

Are you going swimming on Tuesdays?
Do you play football on Saturdays?
Do you go to a Youth Club on Thursdays?
Do you play music on Fridays?
Is Friday Fish and Chips day?

Tagged with: iteration, Python, Selection

Sweet Shop

Posted on November 12, 2015 by Administrator Posted in Computer Science, Python - Intermediate, Python Challenges, Solved Challenges

Have you ever been in a sweet shop to buy sweets? For this challenge we are going to spend £5 in a sweet shop hence we need to find out how many sweets we can afford. We will want to pick and mix sweets until we have spent all our money.

To help us buy our sweets we are going to write a program that will help us decide how many sweets we can afford while allowing us to pick and mix different types of sweets.

Here are the sweets available in the shop:

Here are the main steps of our program which will:

Display a price list of all the sweets available in the shop,
Ask the end-user how much they would like to spend,
Ask the user which sweet they would like to buy and how many of them they would like (A to E),
Allow the user to enter X (instead of the A to E letter for a sweet) to stop buying more sweets,
Check whether the use can afford these and if they can, calculate and display how much money they have left,
Repeat steps 3 to 5 for as long as the user has some money left.

Now let’s see how a flowchart can help us describe these steps further:

Your task:

Use the above flowchart to complete 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: Flowchart, Python

The window cleaner’s quote

Posted on November 12, 2015 by Administrator Posted in Computer Science, Python - Beginner, Python Challenges, Solved Challenges

A window cleaner uses the following pricing policy to calculate how much to charge for cleaning all the windows of his customer’s dwelling. This pricing policy is based on the number of windows that need to be cleaned and works as follows:

All quoted prices include a fixed call out fee of £10,
Then, the first five windows are charged at £2 each,
The next five windows are charged at £1.50 each,
Any additional windows are charged at £1 each.

Your task is to write a computer program that prompts the end-user to enter the number of windows of their dwelling. The program will then calculate the quoted price using the pricing policy described above and display it to the end-user.

Test Plan

Now that you have implemented the cost calculator for the house cleaner, you are going to test your code by completing the following tests: see test plan below. For each test compare the outcome of your program with the expected outcome. If these are different then you’ll need to review and tweak your code.

Test #	Input values	Expected outcome	Actual outcome
1	Number of windows: 3	Cost: £16
2	Number of windows: 5	Cost: £20
3	Number of windows: 7	Cost: £23
4	Number of windows: 9	Cost: £26
5	Number of windows: 10	Cost: £27.50
6	Number of windows: 11	Cost: £28.50
7	Number of windows: 13	Cost: £30.50
8	Number of windows: 15	Cost: £32.50

Extension Task:

At the beginning of the year, the house cleaner wants to attract new customers by offering a 10% discount to all quoted prices.

Adapt your code to include a 10% discount in the quoted price.

Solution

Solution...

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

Tagged with: Arithmetic, Python, Selection

Gradient Animation

Posted on November 9, 2015 by Administrator Posted in Computer Science, Python - Intermediate, Python Challenges, Solved Challenges

In this challenge we are going to create some animated gradients by progressively changing the colour of the screen from one colour (e.g. red) to another (e.g. yellow).

RGB Colour Codes

Did you know that every colour on the screen can be represented using an RGB code (Red, Green, Blue) code. This code consists of three numbers between 0 and 255, indicating how much red, green and blue are used to recreate the colour.

For instance the RGB code for:

Red is (255,0,0)
Green is (0,255,0)
Blue is (0,0,255)
Yellow is (255,255,0)
Orange is (255,165,0)

Check the following RGB Color picker to see how RGB codes work:

Learning Objectives

By completing this code we will investigate how for loops work to iterate through the code a fixed number of times.

We will use an increment in our loop that will go up (increment) by 1 after each iteration, to count from 0 to 255. We will see that we can also use a negative step to count down from 255 to 0.

Gradient #1:

Our first animation will be based on the following gradient:

It will consist of:

256 frames to shade from red (255,0,0) to yellow (255,255,0)
+ another 256 frames to shade from yellow (255,255,0) back to red (255,0,0)
It will repeat the above steps 3 times so in total will consist of (256 + 256) x 3 = 1536 frames!

Check the code below: If this code does not work in Internet Explorer, try to access this webpage using Google Chrome.

Gradient #2: From red (255,0,0) to blue (0,0,255) to red (255,0,0)

This code is slightly different as we want the red code to decrement from 255 to 0 while the blue code increments from 0 to 255. Check how it’s done in the code below:

Gradient #3: From cyan (0,255,255) to magenta (255,0,255) to cyan (0,255,255)

Tweak the code in one of the trinkets above to implement this gradient.

Gradient #4: From cyan (0,255,255) to yellow (255,255,0) to cyan (0,255,255)

Tweak the code in one of the trinkets above to implement this gradient.

Gradient #5: From green (0,255,0) to yellow (255,255,0) to magenta (255,0,255) to cyan (0,255,255) to green (0,255,0)

Tweak the code in one of the trinkets above to implement this gradient.

Gradient #6: From black (0,0,0) to white (255,255,255) to black (0,0,0)

Tweak the code in one of the trinkets above to implement this gradient.

Solution...

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

Tagged with: iteration, Python, RGB

My Charts

Posted on November 9, 2015 by Administrator Posted in Computer Science, Python - Intermediate, Python Challenges

For this challenge we are going to use Python turtle to create some charts: Column charts, line charts and radar charts.

First we need a data set. We will use the following data that shows the market share of the four most popular browsers in 2015.

Web-browser	Percentage
Chrome	44%
Safari	20%
IE / Edge	14%
Firefox	12%
Other	10%

Your Challenge

Using Python Turtle, create the following charts:

Python Turtle

Looking at the following code can you explain the purpose of each Python Turtle instructions:

myPen.color(“red”)
myPen.forward(100)
myPen.right(90)
myPen.left(45)
myPen.penup()
myPen.pendown()
myPen.goto(0,0)
myPen.beginfill()
myPen.end_fill()
myPen.begin_fill()
myPen.write(“Hello World”, None, “center”, “16pt bold”)

(x,y) coordinates using Python Turtle?

On this trinket widget the turtle screen is 400 pixels wide by 400 pixels high. So:

the top left corner coordinates are (-200,200)
the top right corner coordinates are (200,200)
the bottom left corner coordinates are (-200,-200)
the bottom right corner coordinates are (200,-200)
the centre of the screen coordinates are (0,0)

Look at the canvas below to understand how (x,y) coordinates work:

Challenge #1: Complete the code

We have started the code by creating a function called drawColumnChart(). This function takes five parameters – the values of the five columns to appear on the chart.

The code below shows you how to draw the first column. Your job consists of completing this code to draw all five columns.

Challenge #2: Line chart

Using a similar approach add a new function called drawLineChart() to draw a line chart using the same five values.

Challenge #3: Radar chart

Using a similar approach add a new function called drawRadarChart() to draw a radar chart using the same five values.

Tagged with: Coordinates, Python Turtle

Penalty Shootout

Posted on October 30, 2015 by Administrator Posted in Computer Science, Python - Beginner, Python Challenges, Solved Challenges

For this challenge you are going to write a computer program where the user tries to score a goal against the computer.

The user will be asked where do they want to shoot and will have to choose one of the following five options:

TL: Top Left,
BL: Bottom Left,
M: Middle,
TR: Top Right,
BR: Bottom Right.

The computer will act as the goal keeper and randomly choose one of these options too.

The program will decide if there is a goal or not by comparing the user’s choice with the computer option.

Complete the code

We have started the code for you. You need to complete it further:

Video Tutorial

Extension Task 1:

Create a second level where the computer can block up to two locations which are next to each other such as:

Bottom left and right left,
Bottom left and middle,
Top right and middle,
etc.

Extension Task 2:

Give the end-user a choice: do they want to shoot the penalty or be the goal keeper? Adapt your code to cater for both options.

Extension Task 3:

Create a program where the computer and the player take it in turn. The program adds up the scores and stops on a best of 5 scores. (e.g. 3-0, 4-1, 4-2, 5-3, 5-4)

Solution...

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

Tagged with: Python, Selection

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

Learning Objectives

Extension Task:

Challenge #1

Challenge #2

Challenge #3

Coding is an Art

Fireworks Code

Your task:

Interactive Fireworks

Learning Objectives

Let’s Get Coding

Your Task

Your task:

Solution...

Test Plan

Extension Task:

Solution

Solution...

RGB Colour Codes

Learning Objectives

Gradient #1:

Gradient #2: From red (255,0,0) to blue (0,0,255) to red (255,0,0)

Gradient #3: From cyan (0,255,255) to magenta (255,0,255) to cyan (0,255,255)

Gradient #4: From cyan (0,255,255) to yellow (255,255,0) to cyan (0,255,255)

Gradient #5: From green (0,255,0) to yellow (255,255,0) to magenta (255,0,255) to cyan (0,255,255) to green (0,255,0)

Gradient #6: From black (0,0,0) to white (255,255,255) to black (0,0,0)

Solution...

Your Challenge

Python Turtle

(x,y) coordinates using Python Turtle?

Challenge #1: Complete the code

Challenge #2: Line chart

Challenge #3: Radar chart

Complete the code

Video Tutorial

Extension Task 1:

Extension Task 2:

Extension Task 3:

Solution...

Recent Posts

Our Latest Book