Tag Archives: strings

Use string extension methods to validate Social Security numbers in C#

Posted on June 19, 2017 by Rod Stephens

This example defines three extension methods that return true if strings contain Social Security numbers. Recall that you must add extension methods to a static class and that the methods must be static. This example begins by defining a Matches … Continue reading →

Posted in extension methods, extensions, regular expressions, strings | Tagged C#, C# programming, example, example program, extension methods, extensions, regular expressions, Social Security numbers, strings, Windows Forms programming | 2 Comments

Understand the @ symbol in C#

Posted on June 17, 2017 by Rod Stephens

The @ symbol can be pretty confusing for some C# developers. I’ve even known a few who have been programming for quite a while but who still have incorrect assumptions about what @ does. In your code (and only in … Continue reading →

Posted in strings, syntax | Tagged @ symbol, C#, C# programming, example, example program, literal, string literal, strings, syntax, underscore, Windows Forms programming | 1 Comment

Use digits of Pi to draw a picture in C#

Posted on March 15, 2017 by RodStephens

The article 10 stunning images show the beauty hidden in pi shows several ways to use Pi to generate pictures. This example demonstrates one of them. The program starts drawing at the origin (0, 0). It then scans through the … Continue reading →

Posted in algorithms, drawing, graphics, mathematics, strings | Tagged algorithms, approximation, C#, C# programming, convergence, digits of Pi, drawing, error, example, example program, graphics, image of pi, mathematics, Pi, Pi Day, pi image, strings, Windows Forms programming | Leave a comment

Look for dates in the digits of Pi in C#

Posted on March 15, 2017 by RodStephens

The example Find patterns within pi in C# looks for patterns within the digits of Pi. You can use that example to look for dates such as 4/1. This example determines whether the first 100 thousand digits of Pi contains … Continue reading →

Posted in algorithms, mathematics, strings | Tagged algorithms, C#, C# programming, dates, dates in pi, digits of Pi, example, example program, mathematics, Pi, Pi Day, strings, Windows Forms programming | Leave a comment

Find patterns within Pi in C#

Posted on March 14, 2017 by RodStephens

March 14 is known as Pi Day because its numeric representation 3/14 includes the first three digits of Pi: 3.14. (At least in the United States. In Europe where they usually write dates month first, Pi Day is July 22 … Continue reading →

Posted in algorithms, mathematics, strings | Tagged algorithms, approximation, C#, C# programming, convergence, digits of Pi, error, example, example program, mathematics, Pi, Pi Day, strings, Windows Forms programming | 1 Comment

Make a case-insensitive dictionary in C#

Posted on March 1, 2017 by Rod Stephens

The example Use a Dictionary to store and retrieve items in C# shows how to use a dictionary to store and retrieve values with keys. By default the Dictionary class is case-sensitive so the keys “Rod Stephens” and “rod stephens” … Continue reading →

Posted in controls, strings | Tagged C#, C# programming, case insensitive, case insensitive dictionary, case sensitive, case sensitive dictionary, controls, dictionary, example, example program, hashtable, lookup, string lookup, strings, Windows Forms programming | 1 Comment

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

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 →