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By returning a null object (i.e., an empty list) instead, there is no need to verify that the return value is in fact a list. The calling function may simply iterate the list as normal, effectively doing nothing. It is, however, still possible to check whether the return value is a null object (an empty list) and react differently if desired.
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.
In Ada, the null statement serves as a NOP. [13] As the syntax forbids that control statements or functions be empty, the null statement must be used to specify that no action is required. (Thus, if the programmer forgets to write a sequence of statements, the program will fail to compile.)
Null functions have several uses. During software development, null functions with the same names and type signatures as a planned functions are often used as stubs—that is, as non-functional placeholders that allow the incomplete body of code to be compiled and tested prior to completion of all planned features.
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.
This is a feature of C# 9.0. Similar to in scripting languages, top-level statements removes the ceremony of having to declare the Program class with a Main method. Instead, statements can be written directly in one specific file, and that file will be the entry point of the program. Code in other files will still have to be defined in classes.
In computing, a null pointer or null reference is a value saved for indicating that the pointer or reference does not refer to a valid object. Programs routinely use null pointers to represent conditions such as the end of a list of unknown length or the failure to perform some action; this use of null pointers can be compared to nullable types ...
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 ...