Entry Fees Calculator using a Flowchart

Posted on March 15, 2018 by Administrator Posted in Computer Science, Python - Beginner, Python Challenges, Solved Challenges

For this challenge you will create a flowchart to explain the process that a computer will have to follow to calculate the entry fees to an aqua park for a small group of visitors or a family.

Below is the price list of the aqua park:

Video Tutorial

Watch the video tutorial for step by step instructions on how to complete this challenge.

Task 1: Design the Flowchart

First you will design the flowchart for your algorithm. The aim is your algorithm is to:

Ask the user how many adult tickets are needed,
Ask the user how many child tickets are needed,
Calculate the total cost of this order,
Decide if this order qualifies for a 5% discount and if so, calculate the new total cost of the order,
Output the total cost of the order.

Online Flowchart Creator (using Google Chrome)

Task 2: Python Code

Once your flowchart is complete, implement your algorithm using Python code.

Task 3: Test Plan

Test #	Type of Test	Input Values	Expected Output	Actual Output
#1	Valid	Adults: 2 Children: 1	Total Cost: £41
#2	Valid	Adults: 1 Children: 0	Total Cost: £15
#3	Valid	Adults: 2 Children: 3	Total Cost: £59.85
#4	Valid	Adults: 5 Children: 12	Total Cost: £196.65
#5	Valid Extreme	Adults: 0 Children: 0	Total Cost: £0
#6	Erroneous	Adults: abc Children: xyz	Error Message

Task 4: Adding extra validation routines

Tweak your code to add some validation routines when capturing user inputs. For instance, you want to make sure that the user only enters a positive integer value when asked for the number of tickets required.

You might find this blog post useful to ensure the user provides an integer value when asked to do so.

Adding validation routines when capturing user inputs is always a good approach to improve your programs and make them more robust.

You can investigate other forms of validation routines on this page.

Solution...

The solution for this challenge is available to full members!
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Tagged with: Flowchart

Flowchart Creator

Posted on March 14, 2018 by Administrator Posted in Computer Science, Computing Concepts

A flowchart is a visual diagram used to describe an algorithm. It enables you to describe the key steps of your algorithms and highlights when the user will be required to input data, when the computer will output/display information to the end-user, when a decision block (Selection / IF Statement) or a loop (Iteration) is used.

A flowchart uses specific shapes including:

Oval shapes to represent the START and END of an algorithm,
Parallelogram shapes to represent interactions with the end-user (INPUT and OUTPUT),
Rectangle shapes to represent a process or a calculation,
Diamond shapes to represent an IF Statement (Selection) or a LOOP (iteration).

Flowchart Task

Try our new online flowchart creator to design your own algorithms.

Recommended Browser: Google Chrome.

To familiarise yourself with this tool, try to reproduce the following flowchart:

Online Flowchart Creator

Tagged with: Flowchart

Stacks and Queues using Python

Posted on March 10, 2018 by Administrator Posted in Algorithms, Computer Science, OOP Concepts, Python - Advanced, Python Challenges

Stacks and Queues are two key data structures often used in programming.

A queue is a FIFO data structure: First-In First-Out in other words, it is used to implement a first come first served approach. An item that is added (enqueue) at the end of a queue will be the last one to be accessed (dequeue).

A stack is a FILO data structure: First-In Last-Out. Imagine a stack of books piled up on a table. When you add (push) a book on top of the pile, it will be the first book that you will then take (pop) from the pile (stack).

Both stacks and queues can easily be implemented in Python using a list and the append(), pop() and remove() functions.

In the following trinket we are creating our own classes, Queue and Stack. Using Object Oriented Programming (OOP) enables us to prevent direct access to the list (defined as a private attribute – This is an example of encapsulation a key concept in OOP). It also enables us to create and name our own methods, pop(), push(), enqueue() and dequeue() to match the terminology used when using stacks or queues.

Your Task…

Update the above Stack Class and Queue Class to have an extra private property called maxCapacity (positive integer value). This property should be initialised based on a parameter passed using the constructor of each class.

The code to push a value to the Stack or enqueue a value to the queue should be amended to only push or enqueue the value if the stack or the queue have not reached their maximum capacity.

Client-Server Technologies in a Web-Based Application

Posted on March 8, 2018 by Administrator Posted in A Level Concepts, Computer Science, Computing Concepts

If you are learning to build websites you will most likely have started learning about HTML, eventually CSS and JavaScript. These three languages are client-side languages which run on your computer through the web-browser.

A website that only relies on client-side languages is called a static website. This means that the webpages remain the same unless you edit the HTML code. To start with (back in the 90s), the World Wide Web was only made of static websites.

Web 2.0

Progressively, the internet evolved to more dynamic websites. We call this web2.0.

Websites such as amazon, eBay, Facebook, etc. are dynamic websites. Their content changes constantly based on the user interactions with the site.

Web2.0 websites are full web applications that use both client-side technologies (HTML, CSS, JavaScript) and server-side technologies such as PHP, ASP, .Net, C#, Python, etc. as well as a database to store and retrieve information from (MySQL, Oracle, SQL Server).

Server-side scripts interact with the database using SQL queries to select, update, insert or delete data. They then combine this data with HTML tags to create HTML, CSS and JavaScript code that is then sent to the client computer to be viewed in the web-browser as a static web page would be viewed.

The following diagram summarises some of the key concepts of client-server web-based applications:

Relational Databases

Posted on March 8, 2018 by Administrator Posted in A Level Concepts, Computer Science, Computing Concepts, Database Concepts

Tables, Records & Fields

A table is a collection of records. Each record is made of fields.

Each field has a data type such as String/Text, Integer, Float/Real, Boolean, Date & Time, etc.

A table is a collection of records. Each record is made of fields.

Primary Keys, Foreign Keys & Relationships

The primary key is a unique identifier for each record.
e.g. the candidate number field is a primary key in the student table.

When a primary key is used to link records between two tables, it becomes a foreign key in the linked table.

There are 3 types of relationships to link tables:

One-to-One Relationships,
One-to-Many Relationships,
Many-to-Many Relationships.

Entity Relationship Diagram (ERD)

En Entity Relationship Diagram is used to represent all the entities/tables with their attributes/fields and the relationships between these entities.

SQL Language

SQL stands for Structured Query Language. SQL is a standard language used to query a relational database. SQL can be used to:

SELECT records from one or more tables
INSERT new records into a table
UPDATE records from a table
DELETE records from a table

The basic syntax of the SQL language is as follows:

SQL can also be used to change the structure of a database e.g. creating, editing or dropping tables and indexes.

Learn how to define your own SQL queries

To recap…

fields

integer

table

records

primary

Boolean

data type

foreign

linked table

identifier

A is a collection of .
Each record is made of

Each field has a such as string/text, , real/float, , date & time, etc.

The key is a unique for each record.

e.g. the candidate number field is a primary key in the student table.

When a primary key is used to link records between two tables, it becomes a key in the .

Tagged with: Database, SQL

Flowchart to Python Code – Star Rating Validation

Posted on March 6, 2018 by Administrator Posted in Computer Science, Python - Beginner, Python Challenges, Solved Challenges

The aim of this Python challenge is to validate a user input using a range check.

In this program, the user will be asked to enter a star rating by entering a number value between 0 and 5. This could for instance be used to rate a movie (5 Stars = Excellent , 0 Star = Disappointing).

The program will check that the end-user has entered a number between 0 and 5 and if not, it will display an error message and repeat the question until a valid rating between 0 and 5 is entered.

Here is the flowchart for our algorithm:

Python Code

You can now complete the Python code to implement this algorithm.

This algorithm is a good example of:

Testing

Now that your code is complete, it is important to test it to see if it is working as expected.

When testing a program, you can use different types of test and test data:

Valid Tests: To check that the program is working fine with acceptable data.
Extreme Tests: To test how your program works when you enter data that is at the limit (lower boundaries, upper boundaries) of what is considered acceptable data.
Erroneous Tests: To try to break the pogram, enter data that is not acceptable, that should be rejected and/or generate an error message.

Test #	Type of Test	Input Values	Expected Output	Actual Output
#1	Valid	Star Rating: 2	Thank You
#2	Valid Extreme	Star Rating: 0	Thank You
#3	Valid Extreme	Star Rating: 5	Thank You
#4	Erroneous	Star Rating: 9	Invalid Star Rating – Try Again Enter a star rating between 0 and 5:
#5	Erroneous	Star Rating: -2	Invalid Star Rating – Try Again Enter a star rating between 0 and 5:
#6	Erroneous	Star Rating: xyz	Invalid Star Rating – Try Again Enter a star rating between 0 and 5:

Extension Task

Did you all your test pass? If not, this means your code could be further improved.

Check this blog post to see if it could help you improve your code further and ensure all tests pass.

Adding validation routines when capturing user inputs is always a good approach to improve your programs and make them more robust.

You can investigate other forms of validation routines on this page.