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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".
In some programming language environments (at least one proprietary Lisp implementation, for example), [citation needed] the value used as the null pointer (called nil in Lisp) may actually be a pointer to a block of internal data useful to the implementation (but not explicitly reachable from user programs), thus allowing the same register to be used as a useful constant and a quick way of ...
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.
When an object value is declared with no argument list (e.g.: MyClass x;) or allocated dynamically with no argument list (e.g.: new MyClass; or new MyClass();), the default constructor of MyClass is used to initialize the object. When an array of objects is declared, e.g. MyClass x[10];; or allocated dynamically, e.g. new MyClass [10].
This can happen in multi-threaded environments, or even in single-threaded environments when other code (typically called in the destruction of some object) resets the global variable before the checking code. The following example shows a way to avoid this problem (see [dead link ] or ; cf. ). But at the cost of not being able to use return ...
But the initialization of the first_name and last_name members are incorrect. This is because if the length of first_name and last_name character arrays are less than 16 bytes, during the strcpy , [ 1 ] we fail to fully initialize the entire 16 bytes of memory reserved for each of these members.
Here, the construct : re(0), im(0) is the initializer list. Sometimes the term "initializer list" is also used to refer to the list of expressions in the array or struct initializer. C++11 provides for a more powerful concept of initializer lists, by means of a template, called std::initializer_list.
The initializer list is required if you have const or reference type data members, or members that do not have parameterless constructor logic. Assignments occur according to the order in which data members are declared (even if the order in the initializer list is different). [3]