Home > Articles > Programming > C#

Understanding C# Types

  • Print
  • + Share This
This chapter is from the book

Other Commonly Used Types

In addition to the standard predefined types, the .NET Framework provides types for other commonly used values. These types do not have aliases in C# like the predefined types but allow the same operations.

Date and Time

Working with date and time values is done with the DateTime structure, which enables you to create values that represent a date and a time, just a date, or just a time value. The two most common ways to create a new DateTime value are to use one of the various constructor overloads or one of the four static parse methods: Parse, ParseExact, TryParse, or TryParseExact.

The DateTime structure provides several properties; the most common are shown in Table 3.2.

Table 3.2. Common DateTime Properties




Gets the date component of the current instance


Gets the day of the month represented by the current instance


Gets the day of the week represented by the current instance


Gets the hour component of the date represented by the current instance


Gets the minute component of the date represented by the current instance


Gets the month component of the date represented by the current instance


Gets a DateTime object that is set to the current date and time, in the local time zone


Gets the time of day for the current instance


Gets the current date


Gets a DateTime object that is set to the current date and time, in Coordinated Universal Time (UTC)


Gets the year component of the date represented by the current instance

When adding or subtracting date or time values, you can use instance methods, which return a new DateTime value rather than modifying the original one. The common DateTime arithmetic methods are shown in Table 3.3.

Table 3.3. Common DateTime Arithmetic Methods




Adds or subtracts the specified number of days


Adds or subtracts the specified number of hours


Adds or subtracts the specified number of minutes


Adds or subtracts the specified number of months


Adds or subtracts the specified number of years

It is also possible to subtract two DateTime values using the subtraction operator, which results in a TimeSpan instance. A TimeSpan represents an interval of time measured as a positive or negative number of days, hours, minutes, seconds, and fractions of a second. To ensure consistency, time intervals are measured in days. You can also add a TimeSpan to or subtract a TimeSpan from a DateTime, both of which result in a new DateTime value.

The common methods and properties of TimeSpan are shown in Table 3.4.

Table 3.4. Common TimeSpan Members




Adds the specified TimeSpan to the current instance


Gets the days component of the time interval represented by the current TimeSpan


Returns a TimeSpan that represents a specified number of days


Returns a TimeSpan that represents a specified number of hours


Returns a TimeSpan that represents a specified number of milliseconds


Returns a TimeSpan that represents a specified number of minutes


Returns a TimeSpan that represents a specified number of seconds


Gets the hours component of the time interval represented by the current TimeSpan


Gets the milliseconds component of the time interval represented by the current TimeSpan


Gets the minutes component of the time interval represented by the current TimeSpan


Gets the seconds component of the time interval represented by the current TimeSpan


Subtracts the specified TimeSpan from the current instance


Gets the value of the current TimeSpan expressed as whole and fractional days


Gets the value of the current TimeSpan expressed as whole and fractional hours


Gets the value of the current TimeSpan expressed as whole and fractional milliseconds


Gets the value of the current TimeSpan expressed as whole and fractional minutes


Gets the value of the current TimeSpan expressed as whole and fractional seconds

Globally Unique Identifiers (GUIDs)

A GUID is a 128-bit integer value that can be used whenever a unique identifier is required that has a low probability of being duplicated. The System.Guid structure enables you to create and compare GUID values. The common members are shown in Table 3.5.

Table 3.5. Common Guid Members




Compares the current instance to the specified Guid


Represents a read-only instance of a Guid whose value is guaranteed to be all zeros


Creates a new instance of the Guid structure


Converts the string representation of a GUID into the equivalent Guid instance


Converts the string representation of a GUID into the equivalent Guid instance, indicating if the conversion was successful

Uniform Resource Identifiers (URIs)

A uniform resource identifier (URI) is a compact representation of a resource available on the intranet or the Internet and can be an absolute URI (like a web page address) or a relative URI that must be expanded with respect to a base URI.

The Uri class enables you to create new URI values and access the parts of a URI, and provides methods for working with URIs, such as parsing, comparing, and combining. Some of the common members are shown in Table 3.6.

Table 3.6. Common Uri Members




Gets the absolute URI


Compares the specified parts of two Uri instances using the specified comparison rules


Converts a URI string to its escaped representation


Gets a value indicating whether the specified Uri is a file URI


Gets a local operating-system representation of a filename


Determines the difference between two Uri instances


Creates a new Uri but does not throw an exception if the Uri cannot be created

An instance of the Uri class is immutable. To create a modifiable URI, use the UriBuilder class. The UriBuilder class enables you to easily change the properties of a URI without creating a new instance for each modification. All the properties shown in Table 3.7 are common to both Uri (where they are read-only) and UriBuilder except for the Uri property, which is only available on UriBuilder.

Table 3.7. Common Uri and UriBuilder Properties




Gets or sets the fragment portion of the URI


Gets or sets the hostname or IP address of a server


Gets or sets the password associated with the user who accesses the URI


Gets or sets the path to the resource defined by the URI


Gets or sets the port number of the URI


Gets or sets any query information included in the URI


Gets or sets the scheme name of the URI


Gets the Uri instance constructed by the specified UriBuilder instance


Gets or sets the username associated with the user who accesses the URI

Listing 3.1 shows how to use the UriBuilder class.

Listing 3.1. Working with UriBuilder

Uri immutableUri = new Uri("http://www.example.com");

UriBuilder mutableUri = new UriBuilder(immutableUri);

mutableUri.Scheme = "https";
mutableUri.Host = "www.example.com";
mutableUri.Path = "exampleFile.html";

Big Integers and Complex Numbers

The System.Numerics.BigInteger type represents an arbitrarily large integer value that has no theoretical upper or lower bound. When a BigInteger instance has been created, you can use it just as you would any of the other integer types, enabling you to perform basic mathematical operations and comparisons. Listing 3.2 shows some of the ways you can use the BigInteger type.

Listing 3.2. Working with BigInteger

BigInteger b1 = new BigInteger(987321.5401);
BigInteger b2 = (BigInteger)435623411897L;
BigInteger b3 = BigInteger.Parse("435623411897");

Console.WriteLine(BigInteger.Pow(Int32.MaxValue, 2));
Console.WriteLine(b2 == b3);
Console.WriteLine(BigInteger.GreatestCommonDivisor(b1, b2));

The System.Numerics.Complex type represents a complex number, in the form of a + bi, where a is the real part, and b is the imaginary part and allows you to

  • Compare two complex numbers to determine equality.
  • Perform arithmetic operations, such as addition, subtraction, multiplication, and division; other numerical operations, such as raising a complex number to a specific power; finding the square root or getting the absolute value; and trigonometric operations, such as calculating the cosine of an angle represented by a complex number.

Listing 3.3 shows some of the ways you can use the Complex type.

Listing 3.3. Working with Complex

Complex c1 = new Complex(10, 2);
Complex c2 = 3.14;
Complex c3 = Complex.FromPolarCoordinates(5, 0.25);
Complex c4 = (Complex)10.2m;

  • + Share This
  • 🔖 Save To Your Account

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information

To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.


Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.


If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.


This site is not directed to children under the age of 13.


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020