CODEWITHSUNDEEP
c++
dustin ledezma
dustin ledezma

Reputation: 635

Can someone explain this C++ syntax?

I'm going through someone else's code and came across the following syntax:

typedef struct abc {

   abc() : member(0){}

   unsigned int member

}

It seems like a class with member variable and a constructor, except it is declared struct. I have two questions here.

  1. Is this syntax supported in C?
  2. What would be a reason to use structs over classes?

Thanks a lot in advance.

PS: how do I format the code?

Upvotes: 2

Views: 353

Answers (6)

shjeff
shjeff

Reputation: 445

This is C++ code, however using typedef struct (that comes from C) in C++ code is awful. There is difference between C and C++ and in C++ you don't need to typedef structs. struct MyStruct is sufficient declaration if you want to refer your struct via MyStruct myStruct;. Mixing C with C++ is bad.

Upvotes: 0

Oliver Charlesworth
Oliver Charlesworth

Reputation: 272447

This is not valid C.

In C++, struct and class are essentially synonyms. The only difference is that members and inheritance are public by default in a struct, and private by default in a class.

There are no hard guidelines on whether to choose struct or class. However, you'll often find people using struct only for simple C-like plain old data structures ("PODs").

Upvotes: 8

Ted Hopp
Ted Hopp

Reputation: 234795

  1. The syntax is supported. The constructor initializes member to 0 and does nothing else.
  2. struct has a default access of public.

Upvotes: 0

wuxb
wuxb

Reputation: 2612

abc() is a constructor of class abc, member is a internal variable, constructor abc defaults set member as 0.

Upvotes: 0

Puppy
Puppy

Reputation: 146900

This is most assuredly just C++. struct and class are identical in C++, except for defaulting to public instead of private for inheritance and class contents.

Upvotes: 3

Codie CodeMonkey
Codie CodeMonkey

Reputation: 7946

In C++, struct and class are essentially the same thing, except that for a struct members are public by default. So just read it as you would a class.

Upvotes: 0

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