Примеры использования Default constructor на Английском языке и их переводы на Русский язык
{-}
-
Official
-
Colloquial
How many default constructors can have class?
The class has an explicit default constructor.
An explicit default constructor, which allows creating an array of objects of this class;
Each class can have only one default constructor.
The default constructor is the constructor of a class that is declared without parameters.
Is it possible to declare a structure in a default constructor?
The default constructor has a special purpose when initializing an array of objects of its class.
However, in the class, you can declare your own default constructor.
A default constructor or a constructor without parameters can not be declared in a structure.
The class defines an explicit default constructor without parameters.
Therefore, there is no need for an additional declaration of the default constructor.
Default constructors take no parameters, instantiating the object members with their appropriate default values.
For all structures, the system determines the default constructor automatically.
The default constructor will automatically be called only if nothing constructors are declared in the class.
Also, the constructor can be without parameters the default constructor.
In the default constructor, all members of the class are filled using the TimeCurrent() function, in the parametric constructor only hour values are filled in.
However, when you create a class object, the compiler automatically calls the default constructor.
If a class has a user-defined constructor, the default constructor is not generated by the compiler.
This means that the other elements will be implicitly initialized to zero or by the default constructor.
As we can see, the class does not contain the explicitly defined default constructor, apparently, the double value assignment to the field_scanData is an error.
The constructor, all parameters of which have default values,is not a default constructor.
For static members of the complex type the default constructor is called; if there is none, then a constructor with default parameters is called.
Anyway, when you create an instance of the class(operator new), the default constructor is called.
In C++, the standard describes the default constructor for a class as a constructor that can be called with no arguments this includes a constructor whose parameters all have default arguments.
If no constructors are declared in a class,the compiler creates a default constructor during compilation.
In this example, when creating the bar object, a default constructor CBar() will be called, in which first a constructor for the parent CFoo is called, and then comes aconstructor for the m_member class member.
In the standard library, certain containers"fill in" values using the default constructor when the value is not given explicitly.
For example, a default constructor for a restaurant bill object written in C++ might set the tip to 15%: Bill(): tip(0.15),// percentage total(0.0){} The drawback to this is that it takes two steps to change the value of the created Bill object.
This means that if a parametric constructor is declared in a class, but a default constructor is not declared, you can not declare the arrays of objects of this class.
In this example, the CFoo class has a declared parametric constructor- in such cases, the compiler does not create a default constructor automatically during compilation.