When is the primitive constructor type actually used?

Question

I know that similar questions have already been asked on SO, but my question is different, so please do not mark it as duplicate or somehow else before you read it completely.

Bjarne Stroustrup in his book C ++ Programming Language says that

10.4.2 Built-in types also have default constructors

also read section 6.2.8 of the same book.

The following links also say that built-in types have default constructors in C ++.

• http://www.informit.com/guides/content.aspx?g=cplusplus&seqNum=15

• http://www.geeksforgeeks.org/c-default-constructor-built-in-types/

But the answers at the following link say that built-in types do not have constructors.

• Do built-in types have default constructors?

Also, read the following links that say expressions such as int i=int(); initiate initialization of the value, which basically ends with zero initialization.

• Does "int a = int ();" sure to give me zero?

Here is a question that I sometimes asked that says what happens in the case of int a=int() in C ++ 98, and I got the answer as initialization by default.

• int a = int (); what happens in c ++ 98?

If I'm not mistaken, there is no mention in the C ++ standard, or the C ++ standard does not mean that primitive types also have constructors. So, from the book of Bjarn Straustup, can I say that it is conceptually true that they have constructors, but there is practically no such thing as a constructor for built-in types? Is this really spoiled text in his book? Or, if this is true, according to the book of Bjarne Straustrup, when are they really called up and used?