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In object-oriented computer programming, a null object is an object with no referenced value or with defined neutral (null) behavior.The null object design pattern, which describes the uses of such objects and their behavior (or lack thereof), was first published as "Void Value" [1] and later in the Pattern Languages of Program Design book series as "Null Object".
C# 6.0 and above have ?., the null-conditional member access operator (which is also called the Elvis operator by Microsoft and is not to be confused with the general usage of the term Elvis operator, whose equivalent in C# is ??, the null coalescing operator) and ?[], the null-conditional element access operator, which performs a null-safe call of an indexer get accessor.
Nullable types are a feature of some programming languages which allow a value to be set to the special value NULL instead of the usual possible values of the data type.In statically typed languages, a nullable type is an option type, [citation needed] while in dynamically typed languages (where values have types, but variables do not), equivalent behavior is provided by having a single null ...
The null coalescing operator is a binary operator that is part of the syntax for a basic conditional expression in several programming languages, such as (in alphabetical order): C# [1] since version 2.0, [2] Dart [3] since version 1.12.0, [4] PHP since version 7.0.0, [5] Perl since version 5.10 as logical defined-or, [6] PowerShell since 7.0.0, [7] and Swift [8] as nil-coalescing operator.
Whether it is a console or a graphical interface application, the program must have an entry point of some sort. The entry point of a C# application is the Main method. There can only be one declaration of this method, and it is a static method in a class. It usually returns void and is passed command-line arguments as an array of strings.
Strings are reference types in Visual Basic .NET, and so capable of being null (as opposed to simply zero-length, empty, strings). For such strings, this function returns True. (For empty strings it returns False.) [21] [18] IsNull(expression) This function determines whether the expression passed as its argument evaluates to Null. A null value ...
Null-terminated strings require that the encoding does not use a zero byte (0x00) anywhere; therefore it is not possible to store every possible ASCII or UTF-8 string. [ 8 ] [ 9 ] [ 10 ] However, it is common to store the subset of ASCII or UTF-8 – every character except NUL – in null-terminated strings.
The empty string is a legitimate string, upon which most string operations should work. Some languages treat some or all of the following in similar ways: empty strings, null references, the integer 0, the floating point number 0, the Boolean value false , the ASCII character NUL , or other such values.