Students are often unsure what the purpose of a dictionary is. As students generally enjoy encryption and can get engaged with the ideas, this lesson gives a concrete example of a dictionary implementation using the simple Atbash encryption cypher.

Code clarity and readability is essential but is all too often an afterthought. This lesson is a guided tour to the “Zen of Python”. The “Zen of Python” is a set of principles for clarity of coding in Python (although useful in any coding language) written by Tim Peters, a famous Python coder and contributer.

This is a programming task that is suitable for a student who has mastered the basics of a programming language such as Java or Python, but needs to be extended by the teacher. It should challenge but not defeat. The solutions will be published in both Java and Python.

This is a proposed solution in Java to the extended task on a 2D array with an insertion sort implemented.

In the Cambridge AS level Computer Science, the past paper questions are rather tedious. This is a slightly easier but much more fun problem which brings in the use of constants, a composite data type (a record) and the CASE selection. It’s based on a computer game scenario which really motivates the students. My year 12’s really enjoyed it.

Methods can call other methods and be recursive. These ideas are used in estimating a value for the Golden Ratio for the Fibonacci sequence. The Golden Ratio can inspire students to research both Fibonacci and the Ratio.

This folder contains instructions and Python code for an extension programming task. The task is to decrypt (crack) a poorly encrypted text file. The Security topic in the Cambridge 9618 Computer Science syllabus is rather dry and this could liven it up. The idea could work for any Computer Science syllabus that involves programming however.

Methods in pseudocode discussed with examples and tasks. This presentation is designed to be shown to the class by the teacher as it’s been explained. Methods are given for the mean of a numerical array and also the standard deviation.

A compilation of notes on Code readability for all coders. We discuss the four main techniques to improve code readability.

This example implements a payroll program that uses pre-conditions and alternatives to pay an end-of-year bonus to employees based on their salary and/or number of months working for the company.

This is the second in a series of articles on the use of pseudocode in the IB Computer Science, it introduces loops and nested loops. There is also a link to an online pseudocode compiler which will execute the code.

Step by step guide to solving linear equations.

The Cambridge syllabus describes the Enumerated data type but students find it hard to remember and use in pseudocode. If they have done or started Object Oriented Programming, then implementing the Enumerated data type could be a good example.

This is the first on a series on using pseudocode in the IB Computer Science syllabus.

After studying Asymmetric Encryption and in particular the RSA algorithm, as an extension, the teacher can use RSA with a relatively small public key to encrypt a plain text file. Students then compete alone or in groups to attack the weak public key to find the private key. This will allow them to decrypt the encrypted file, follow the instructions set out there (e.g send an email with the code used to the teacher’s school email) and win the prize. This project generated great enthusiasm in my upper sixth students and is well worth a try. I will upload a pack that will include code to generate the encrypted file, teacher’s notes, solution code and more as a separate download.

These notes on System software aim to organize the functions of an operating system by levels, discussing the functions and assigning them to level(s). It’s aimed at introductory level , eg. AS Computer Science or IB Computer Science.

A brief introduction to 2D arrays in Java with example code. A 2D array is visualized an an array of arrays being similar in conceptual structure as an Excel spreadsheet.

The basics of reading and writing text files is introduced using a simple class, BufferedReader. The sooner that students can use text files in their programming the better as more complex problems can be programmed.