Monthly Archives: February 2017

Understand string equality testing in C#

Posted on February 28, 2017 by RodStephens

To really understand this example, you need to know about string interning, equality testing, and operator overloading. Interning First, interning. To save space, .NET uses an intern pool to store literal strings at compile time. If the program contains a … Continue reading →

Posted in strings, syntax | Tagged ==, C#, C# programming, equality, Equals, example, example program, intern, intern pool, string intern, strings, syntax, Windows Forms programming | Leave a comment

Use a Dictionary to store and retrieve items in C#

Posted on February 27, 2017 by Rod Stephens

This example demonstrates a Dictionary. A Dictionary is basically a strongly typed Hashtable. A Hashtable stores key/value pairs in a way that makes looking up values extremely fast. For example, suppose you have an employee database that uses EmployeeId values … Continue reading →

Posted in controls, strings | Tagged C#, C# programming, controls, dictionary, example, example program, hashtable, lookup, string lookup, strings, Windows Forms programming | Leave a comment

Compare the performance of string comparison methods in C#

Posted on February 25, 2017 by Rod Stephens

This example uses the following code to make four strings: string value0 = “AAAAAAAAAAAAAAAAAAAAAA”; string value1 = “AAAAAAAAAAAAAAAAAAAAAA”; string value2 = “AAAAAAAAAAAAAAAAAAAAAB”; string value3 = “BAAAAAAAAAAAAAAAAAAAAA”; It then uses several methods for comparing the first string with the others. For … Continue reading →

Posted in performance, strings | Tagged C#, C# programming, compare strings, example, example program, performance, String.Compare, strings, ToLower, Windows Forms programming | Leave a comment

Compare the performance of switch and if statements in C#

Posted on February 24, 2017 by Rod Stephens

This example compares the performance of switch and if-else statements. Both do roughly the same thing: they check a series of conditions until they find one that is true and then skip the rest. This example compares the speeds of … Continue reading →

Posted in performance, syntax | Tagged C#, C# programming, example, example program, if else, if then, if then else, if-else statement, if-then statement, if-then-else statement, performance, switch, switch statement, syntax, Windows Forms programming | Leave a comment

Draw, move, and delete line segments in VB.NET

Posted on February 23, 2017 by RodStephens

This progra lets you draw, move, and delete line segments from a drawing. It’s a Visual Basic .NET version of the example Draw, move, and delete line segments in C# made by request. Click and drag to draw line segments. … Continue reading →

Posted in drawing, graphics | Tagged delete line segments, draw line segments, drawing, example, example program, graphics, line segments, MouseDown, MouseMove, MouseUp, move end points, move line segments, trash can icon, trash icon, trashcan icon, VB.NET, VB.NET programming, Visual Basic, Visual Basic .NET, Visual Basic .NET programming, Visual Basic programming, Windows Forms programming | Leave a comment

Convert a Rectangle into a RectangleF and vice versa in C#

Posted on February 21, 2017 by Rod Stephens

The RectangleF structure has an overloaded assignment operator = that lets you simply set a RectangleF equal to a Rectangle, so converting a Rectangle into a RectangleF is easy. That makes sense because converting from Rectangle to RectangleF is a … Continue reading →

Posted in drawing, graphics | Tagged C#, C# programming, drawing, example, example program, graphics, Rectangle, Rectangle structure, RectangleF, RectangleF structure, Windows Forms programming | Leave a comment

Make a hangman game in C#

Posted on February 20, 2017 by Rod Stephens

Special thanks to Jeff Scarterfield for the skeleton drawing used by the program. This example builds a simple hangman game that uses the dictionary created by the example Use LINQ to select words of certain lengths from a file in … Continue reading →

Posted in algorithms, files, games, graphics, strings | Tagged algorithms, C#, C# programming, example, example program, files, games, graphics, hangman, hangman game, random, strings, Windows Forms programming | Leave a comment

Use LINQ to select words of certain lengths from a file in C#

Posted on February 16, 2017 by Rod Stephens

This example uses LINQ to read a file, remove unwanted characters, select words of a specified length, and save the result in a new file. Recently I needed a big word list so I searched around for public domain dictionaries. … Continue reading →

Posted in algorithms, files, LINQ | Tagged algorithms, C#, C# programming, dictionary, example, example program, files, LINQ, select words, Windows Forms programming, word list, WriteAllLines | 2 Comments

Draw a golden spiral in C#

Posted on February 15, 2017 by Rod Stephens

This example shows how to draw a golden spiral (or phi spiral) in C#. The example Draw a nested series of golden rectangles in C# draws nested rectangles and connects their corners to make a square “spiral.” This example makes … Continue reading →

Posted in algorithms, drawing, graphics, mathematics | Tagged algorithms, C#, C# programming, drawing, example, example program, golden mean, golden ratio, golden rectangles, golden spiral, graphics, mathematics, phi, phi spiral, Windows Forms programming | 3 Comments

Draw a nested series of golden rectangles in C#

Posted on February 14, 2017 by Rod Stephens

This program draws golden rectangles, rectangles whose side ratio is equal to φ. For information on φ, see Examine the relationship between the Fibonacci sequence and phi in C#. The program first draws a golden rectangle. It then removes the … Continue reading →