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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 safety based in types appeared first in Ceylon, followed soon by TypeScript. The C# language implements compile-time null safety check since version 8. However, to stay compatible with older versions of the language, the feature is opt-in on a per project or per file basis.
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.
In Gosu, the ?: operator returns the right operand if the left is null as well. In C#, the null-conditional operator, ?. is referred to as the "Elvis operator", [10] but it does not perform the same function. Instead, the null-coalescing operator?? does. In ColdFusion and CFML, the Elvis operator was introduced using the ?: syntax.
For example, the pyramid of doom is commonly seen when checking for null pointers or handling callbacks. [1] Two examples of the term are related to a particular programming style in early versions of JavaScript, [2] and the nesting of if statements that occurs in object-oriented programming languages when one of the objects may be a null ...
Boxing is the operation of converting a value of a value type into a value of a corresponding reference type. [15] Boxing in C# is implicit. Unboxing is the operation of converting a value of a reference type (previously boxed) into a value of a value type. [15] Unboxing in C# requires an explicit type cast. Example: