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Initialization of C struct in C++ [duplicate]

Is it possible to initialize structs in C++ as indicated below:

struct address {
    int street_no;
    char *street_name;
    char *city;
    char *prov;
    char *postal_code;
};

address temp_address = { .city = "Hamilton", .prov = "Ontario" };

The links here and here mention that it is possible to use this style only in C. If so why is this not possible in C++? Is there any underlying technical reason why it is not implemented in C++, or is it bad practice to use this style. I like using this way of initializing because my struct is big and this style gives me clear readability of what value is assigned to which member.

Please share with me if there are other ways through which we can achieve the same readability.

I have referred the following links before posting this question:

  1. C/C++ for AIX
  2. C Structure Initialization with Variable
  3. Static structure initialization with tags in C++
  4. C++11 Proper Structure Initialization
like image 724
Dinesh P.R. Avatar asked Nov 24 '22 22:11

Dinesh P.R.


2 Answers

If you want to make it clear what each initializer value is, just split it up on multiple lines, with a comment on each:

address temp_addres = {
  0,  // street_no
  nullptr,  // street_name
  "Hamilton",  // city
  "Ontario",  // prov
  nullptr,  // postal_code
};
like image 69
Wyzard Avatar answered Nov 26 '22 12:11

Wyzard


After my question resulted in no satisfying result (because C++ doesn't implement tag-based init for structures), I took the trick I found here: Are members of a C++ struct initialized to 0 by default?

For you it would amount to do that:

address temp_address = {}; // will zero all fields in C++
temp_address.city = "Hamilton";
temp_address.prov = "Ontario";

This is certainly the closest to what you wanted originally (zero all the fields except those you want to initialize).

like image 41
Gui13 Avatar answered Nov 26 '22 13:11

Gui13