Trivial classes in C++

When a class or struct in C++ has compiler-provided or explicitly defaulted special member functions, then it is a trivial type. It occupies a contiguous memory area. It can have members with different access specifiers.

Trivial types have a trivial default constructor, trivial copy constructor, trivial copy assignment operator and trivial destructor. In each case, trivial means the constructor/ operator/ destructor is not user-provided and belongs to a class that has :

• No virtual functions or virtual base classes,
• No base classes with a corresponding non-trivial constructor/operator/destructor
• No data members of class type with a corresponding non-trivial constructor/operator/destructor

The following examples show trivial types :

/*Since there are no explicit constructors,
there exists a default constructor*/
struct Trivial {
    int i;

private:
    int j;
};

/* In Trivial2 structure, the presence of the
   Trivial2(int a, int b) constructor requires
   that you provide a default constructor. For
   the type to qualify as trivial, we must
   explicitly default that constructor.*/
struct Trivial2 {
    int i;
    Trivial2(int a, int b)
    {
        i = a;
    }
    Trivial2() = default;
};

Reference : https://msdn.microsoft.com/en-us/library/mt767760.aspx

This article is contributed by Rohit Thapliyal. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.

My Personal Notes arrow_drop_up

Save