C# String Class

In C#, a string is a sequence of Unicode characters or an array of characters. The range of Unicode characters will be U+0000 to U+FFFF. The array of characters is also termed as the text. So the string is the representation of the text.

A string is represented by a class System.String. The String class is defined in the .NET base class library. In other words, a String object is a sequential collection of System.Char objects, which represent a string.

Characteristics of String Class:

• The System.String class is immutable, i.e., once created, its state cannot be altered.
• Provides the properties like length used to get a total number of characters present in the given string.
• String objects can include a null character, which counts as part of the string’s length.
• It provides the position of the characters in the given string called as indexes.
• It allows empty strings. Empty strings are valid instances of String objects that contain zero characters.
• It also supports searching strings, comparison of strings, testing of equality, modifying the string, normalization of string, copying of strings, etc.
• It also provides several ways to create strings like using a constructor, using concatenation, etc.

Example: Use of String class to print a message.

Hello Geek

Constructor

Example: Creating a string using String class constructor String(Char*, Int32) and String([]).

GEEKS
EEEEE

Properties

In C# the String class has two properties.

• Chars[Int32]: Gets the Char object at a specified position in the current String object.
• Length: Gets the number of characters in the current String object.

Example: Using the Properties of string class.

G e e k s f o r G e e k s 

Methods

Example: Using Copy() and Compare() methods from the String class.

Result of Compare Method: True
Original Strings: str1 = 'GeeksforGeeks' and str2 ='geeks'

After Copy method

Strings are str1 = 'GeeksforGeeks' and str2='GeeksforGeeks'

Operators

There are two operators string class

• Equality(String, String): Determines whether two specified strings have the same value.
• Inequality(String, String): Determines whether two specified strings have different values.

Example: Using Equality and Inequality operators of string class.

The strings "WelcomeToGeeks" and "WelcomeToGeeks" equal: True
The strings "WelcomeToGeeks" and "WelcomeToGeeks" not equal: False

Important Points:

• The maximum size of the String object in memory can be 2GB or about 1 billion characters.
• A string that has been declared but has not been assigned a value is null. Attempting to call methods on that string throws a NullReferenceException.
• String Class can not be inherited because it is a sealed class.
• String Class present in the System namespace.