C++ struct keyword usage

Question

I'm setting up a basic socket server following this guide: https://www.geeksforgeeks.org/socket-programming-cc/

So, I know that when you use the keyword struct it's to define a data structure, but as you can see in the example, it creates an instance of sockaddr_in using the structure keyword, but it's not for creating/defining the structure, it's to create an instance.

So I'm wondering why in this guide to define a sockaddr_in structure he puts the 'structure' keyword before, I tried it without and it compiles all correctly.

Is there any reason behind?

in c you need to put the keyword when declaring an instance of a struct. Iirc it is something about structs living in a different namespace. Almost sure there is a duplicate somewhere... — 463035818_is_not_an_ai, Aug 16 '18 at 07:25
well, not the best dupe, but the answer explains the reasons — 463035818_is_not_an_ai, Aug 16 '18 at 07:28

score 7 · Answer 1 · answered Aug 16 '18 at 07:25

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using struct when declaring an instance of a struct comes from C. It is optional in C++.

answered Aug 16 '18 at 07:25

Eyal Cinamon

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Kaldrr · Answer 2 · 2018-08-16T07:42:19.933

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The source files shown in your link are both written in C, not C++. In C, when declaring an instance of a struct, you need the struct keyword, like this.

struct sockaddr_in address;

In C++ you don't need to do this anymore.

edited Aug 16 '18 at 07:42

answered Aug 16 '18 at 07:25

Kaldrr

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"needed" ? I dont know C, but I think it you still need it – 463035818_is_not_an_ai Aug 16 '18 at 07:31

score 1 · Answer 3 · answered Aug 16 '18 at 07:27

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The article that you've mentioned is written in C, which in C when you create a struct and you try to use it as a type, you have to mention that it's a struct. If you want to give up on the struct, you can read more about the typedef operator.

answered Aug 16 '18 at 07:27

Ido H Levi

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C++ struct keyword usage

3 Answers3

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