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Learn what is Trivial Default Constructor in C++

The Constructor in C++ is a function, a method in the class, but it is a ‘special method’ that is automatically called when an object of a class is created. We don’t need to call this function. Whenever a new object of a class is created, the Constructor allows the class to initialize member variables or allocate storage. This is why the name Constructor is given to this special method.

There are different contractor types and the Default Constructor in classes is one of these. This method not only used in classes but also used with struct and union data types Do you want to learn what is default constructor or what kind of methods we have that we can declare and use default constructors? In this post, we will try to explain the Default Constructor with examples.

Default Constructor is a constructor type in Classes that is called when class is defined with no arguments, or it is defined with an empty parameter list, or with default arguments provided for every parameter. A type with a public default constructor is Default Constructible; There are different methods to use this Default Constructor and one of the terms that we meet sometimes is Trivial Default Constructor. If you are looking for how do we declare a trivial default constructor, please read below.

Trivial Default Constructor

Trivial Default Constructor is a constructor that does not act. All data types compatible with the C are trivially default-constructible.

The Default Constructor for class is Trivial if all listed conditions below are provided,

  • The constructor is not defined by the user, not defined implicitly or not defaulted on its first declaration
  • The class has no virtual member functions
  • The class has no virtual base classes
  • The class has no non-static members with default initializers.(since C++11)

and also note that,

  • Every direct base of the class has a trivial default constructor
  • Every non-static member of class type has a trivial default constructor

Here is a full example about Trivial Default Constructor,

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About author

Dr. Yilmaz Yoru has 35+ years of coding with more than 30+ programming languages, mostly C++ on Windows, Android, Mac-OS, iOS, Linux, and some other operating systems. He was born in 1974, Eskisehir-Turkey, started coding in college and graduated from the department of Mechanical Engineering of Eskisehir Osmangazi University in 1997. He worked as a research assistant at the same university for more than 10 years. He received his MSc and PhD degrees from the same department at the same university. Since 2012, he is the founder and CEO of Esenja LLC Company. He has married and he is a father of a son. Some of his interests are Programming, Thermodynamics, Fluid Mechanics, Artificial Intelligence, 2D & 3D Designs, and high-end innovations.
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