Substitution Ciphers

The Secret Code Book is a gentle introduction to substitution ciphers where each chapter eases young readers into the concept of rotation ciphers and work their way up to the Vigenère cipher. Along the way, readers will also learn about geometric approaches to secret codes such as the Pigpen cipher…

Secret Code Book

Congratulations on reading this book! Be sure to go back to the introduction and complete the bonus mission. I hope you have learned something new and now have a better understanding of cryptography.

Remember, this is a rich subject and we have only touched the surface. You are encouraged to…

Using any book to create a secret code.

Another way to disguise messages is to use specific words in a common book or essay. Individual words can be identified by page, line and word number separated by periods. For example, using this book we have, ( NOTE: Works for printed copy only.)

That is, we find on the…

Using an index, pointer, and iterator to cycle through a vector.

TL;DR —The goal is to quickly review C++ syntax needed to iterate through a vector using a for loop. We will use an index, pointer, and iterator. You will find the full code listing at the bottom of this post.

Let’s begin by instantiating an integer vector named ageVector.


Free printable graph paper and graphing lines help.

TL;DR — All you really need is a few sheets of graph paper. Here you will find printable sheets. In addition, there are some notes and videos for actually graphing lines found in any Beginning Algebra course.

Your graphs will look better if you have graph paper.

However, you will…

Your algebra teacher lied to you!

Well, not really. The title is just bait to get every Algebra teacher ever to click. Since you are here, give me a few minutes to explain with three common examples.

TL:DR — The truth can be affected by the space of numbers allowed for the coefficients of a polynomial…

TL;DR — An arrow in the complex plane!

Before we can lay our eyes on the beautiful imaginary unit i, we have to quickly review complex numbers. Alright, we know from a basic math class that i is defined as the square root of −1.

And to express a square root of a negative number in terms of…

John Redden

Professor and Author

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