Tag Archives: algorithms

Find Mersenne primes in C#

Posted on July 16, 2018 by RodStephens

Mersenne primes are prime numbers of the from 2n – 1 for some integer n. For example, 22 – 1 = 4 – 1 = 3 and 3 is prime, so 3 is a Mersenne prime. This example uses a … Continue reading →

Posted in algorithms, mathematics | Tagged algorithms, C#, C# programming, example, example program, mathematics, Mersenne primes, prime numbers, primes, Windows Forms programming | Leave a comment

Convert between ragged arrays and two-dimensional arrays

Posted on July 10, 2018 by RodStephens

Ragged arrays are arrays that hold other arrays, as opposed to two-dimensional arrays. They are called “ragged arrays” because they work like two-dimensional arrays (or higher-dimensional arrays) where each row in the array can hold a different number of elements. … Continue reading →

Posted in algorithms, arrays, extension methods, generic | Tagged algorithms, arrays, C#, C# programming, example, example program, extension methods, generic, multi-dimensional arrays, ragged arrays, two-dimensional arrays, Windows Forms programming | Leave a comment

Perform image hashing in C#

Posted on July 6, 2018 by RodStephens

Image hashing or (perceptual image hashing) attempts to reduce an image to a concise code that represents the image so you can compare it to other images to see if they are the same. This example uses a difference hash … Continue reading →

Posted in algorithms, graphics, image processing | Tagged algorithms, C#, C# programming, example, example program, graphics, image processing, Windows Forms programming | Leave a comment

Draw the spiral of Theodorus in C#

Posted on June 19, 2018 by RodStephens

The spiral of Theodorus (which is also called the square root spiral, Einstein spiral, and Pythagorean spiral) was first devised by the Greek mathematician Theodorus of Cyrene during the 5th century BC. The spiral consists of a sequence of right … Continue reading →

Posted in algorithms, drawing, graphics, mathematics | Tagged algorithms, C#, C# programming, drawing, Einstein spiral, example, example program, graphics, mathematics, Pythagorean spiral, root spiral, spiral, spiral of Theodorus, Windows Forms programming | Leave a comment

Add LINQ to autocomplete in C#

Posted on June 15, 2018 by Rod Stephens

This example adds LINQ to the example Improve autocomplete suggestion in C#. It adds LINQ in two places: when it loads the list of words and when the program searches for the best matches that begin with a particular letter. … Continue reading →

Posted in algorithms, LINQ, strings | Tagged algorithms, AutoComplete, autocomplete words, autocompletion, C#, C# programming, edit distance algorithm, example, example program, LINQ, smart phone, smartphone, strings, suggest words, Windows Forms programming | Leave a comment

Improve autocomplete suggestion in C#

Posted on June 14, 2018 by Rod Stephens

This example improves on the example Suggest autocomplete words in C#. The previous example loads all of its words into a big array. Then, to find the words that start with a particular letter, the program uses a binary search … Continue reading →

Posted in algorithms, strings | Tagged algorithms, AutoComplete, autocomplete words, autocompletion, C#, C# programming, edit distance algorithm, example, example program, LINQ, smart phone, smartphone, strings, suggest words, Windows Forms programming | 1 Comment

Suggest autocomplete words in C#

Posted on June 13, 2018 by Rod Stephens

This example shows one way that a program can suggest words for the user. When I type something on my phone, it displays a list of possible words for autocomplete below the editing area. For example, if I type “gping” … Continue reading →

Tile a bitmap with a string in C#

Posted on June 5, 2018 by RodStephens

I recently needed a bitmap tiled with a string for a book I’m working on, so I wrote this program to make it. The program lets you click on the font name, dimensions, or colors to select those values. When … Continue reading →

Posted in algorithms, graphics, image processing | Tagged algorithms, Bitmap, C#, C# programming, example, example program, graphics, image processing, repeat string, tile bitmap, Windows Forms programming | Leave a comment

Color the solutions to the “Find the squares in C#” puzzle

Posted on June 4, 2018 by RodStephens

The post Solve the “Find the squares in C#” puzzle explained how you can find solutions to the puzzle described in the post Puzzle: Find the squares in C#. This example shows how you can color the solutions so squares … Continue reading →

Posted in algorithms, games, graphics, mathematics | Tagged algorithms, C#, C# programming, example, example program, find the squares, games, graphics, mathematics, puzzles, squares puzzle, Windows Forms programming | Leave a comment

Solve the “Find the squares in C#” puzzle

Posted on June 1, 2018 by Rod Stephens

This post shows how to solve the puzzle Puzzle: Find the squares in C#. The program howto_square_puzzle_solution uses the following code to define the puzzle’s 11 solutions. // Small squares. Solutions.Add(new int[] { 0, 1, 4, 3 }); Solutions.Add(new int[] … Continue reading →