struct in C++

[Garma]

In VC++ compiler

struct what
{
int a;
int b;
};

In C, an struct of type "what" is created like: struct what this;
In C++, an object of type "what" can be instantiated like this: what this;
Is this defined in C++ Standard or just VC++ compiler I am using
implemented?

[pandy.song]

Re: struct in C++

C++ Standard defines it. Not VC++ compiler.

"Garma" <Garmatu@nosyss erv.com> wrote in message
news:Q_mNb.3848 8$6y6.823264@bg tnsc05-news.ops.worldn et.att.net...[color=blue]
> In VC++ compiler
>
> struct what
> {
> int a;
> int b;
> };
>
> In C, an struct of type "what" is created like: struct what this;
> In C++, an object of type "what" can be instantiated like this: what this;
> Is this defined in C++ Standard or just VC++ compiler I am using
> implemented?
>
>
>
>[/color]

[Andrey Tarasevich]

Re: struct in C++

Garma wrote:[color=blue]
> In VC++ compiler
>
> struct what
> {
> int a;
> int b;
> };
>
> In C, an struct of type "what" is created like: struct what this;
> In C++, an object of type "what" can be instantiated like this: what this;
> Is this defined in C++ Standard or just VC++ compiler I am using
> implemented?[/color]

Yes, it is defined in C++ standard. In C++ in this particular context
(declaration) you can do it either way. Keep in mind though that in C++
'this' is a keyword. You can't create an object named 'this'.

--
Best regards,
Andrey Tarasevich

[E. Robert Tisdale]

Re: struct in C++

Garma wrote:
[color=blue]
> In VC++ compiler
>
> struct what {
> int a;
> int b;
> };
>
> In C, an [object] of type "struct what" is created like this:[/color]
[color=blue]
> struct what this;[/color]
[color=blue]
> In C++, an object of type "what" can be instantiated like this:
>
> what this;
>
> Is this defined in C++ Standard?[/color]

No.
'this' is a C++ keyword.
[color=blue]
> Or just VC++ compiler I am using implemented?[/color]

The ANSI/ISO C standards define the C programming language.
The ANSI/ISO C++ standards define the C++ programming language

If you define:

typedef struct what {
int a;
int b;
} what;

in C, you can create an object of type "struct what" like this:

what w;

[Nick Hounsome]

Re: struct in C++


"Garma" <Garmatu@nosyss erv.com> wrote in message
news:Q_mNb.3848 8$6y6.823264@bg tnsc05-news.ops.worldn et.att.net...[color=blue]
> In VC++ compiler
>
> struct what
> {
> int a;
> int b;
> };
>
> In C, an struct of type "what" is created like: struct what this;
> In C++, an object of type "what" can be instantiated like this: what this;[/color]

No it can't - 'this' is a keyword.
[color=blue]
> Is this defined in C++ Standard or just VC++ compiler I am using
> implemented?
>[/color]

Standard - but you can write:
struct what a;
In both C and C++ and it is still needed in some places in C++.
You can also get more C++ like in C by using:
typedef struct
{
int a;
int b;
} what;
what a;[color=blue]
>
>
>[/color]

[Howard]

Re: struct in C++


"E. Robert Tisdale" <E.Robert.Tisda le@jpl.nasa.gov > wrote in message > If
you define:[color=blue]
>
> typedef struct what {
> int a;
> int b;
> } what;
>
> in C, you can create an object of type "struct what" like this:
>
> what w;
>[/color]

You've got an extra "what" there, before the {, don't you? Should be just:

typedef struct {
int a;
int b;
} what;
....
what w;

-Howard

[jeffc]

Re: struct in C++


"Garma" <Garmatu@nosyss erv.com> wrote in message
news:Q_mNb.3848 8$6y6.823264@bg tnsc05-news.ops.worldn et.att.net...[color=blue]
> In VC++ compiler
>
> struct what
> {
> int a;
> int b;
> };
>
> In C, an struct of type "what" is created like: struct what this;
> In C++, an object of type "what" can be instantiated like this: what this;
> Is this defined in C++ Standard or just VC++ compiler I am using
> implemented?[/color]

Standard - new "feature" of C++ (over C).

[E. Robert Tisdale]

Re: struct in C++

Howard wrote:
[color=blue]
> E. Robert Tisdale wrote:
>
> If you define:
>[color=green]
>>typedef struct what {
>> int a;
>> int b;
>> } what;
>>
>>in C, you can create an object of type "struct what" like this:
>>
>>what w;[/color]
>
>
> You've got an extra "what" there, before the {, don't you? Should be just:
>
> typedef struct {
> int a;
> int b;
> } what;
> ...
> what w;[/color]

typedef struct what what;

typedef struct other {
what* p;
// . . .
};

struct what {
int a;
int b;
};

what w;

[Jeff Schwab]

Re: struct in C++

Howard wrote:[color=blue]
> "E. Robert Tisdale" <E.Robert.Tisda le@jpl.nasa.gov > wrote in message > If
> you define:
>[color=green]
>>typedef struct what {
>> int a;
>> int b;
>> } what;
>>
>>in C, you can create an object of type "struct what" like this:
>>
>>what w;
>>[/color]
>
>
> You've got an extra "what" there, before the {, don't you? Should be just:
>
> typedef struct {
> int a;
> int b;
> } what;
> ...
> what w;
>
> -Howard
>
>[/color]

The first "what" is the struct's tag. The second is an alternative name
(via typedef) for the type "struct what".