«

what is the size of an class with not data members?
ex:
class A {
};

also
sizeof ?
class A{
int f(){
cout<<"Hello";
}
};

<> wrote in message
news: oups.com...
> what is the size of an class with not data members?
> ex:
> class A {
> };
>
> also
> sizeof ?
> class A{
> int f(){
> cout<<"Hello";
> }
> };

Usually 1. Why don't you try it?

On Sep 5, 8:51 am, "Jim Langston" <tazmas...@rocketmail.com> wrote:
> <deepakvs...@gmail.com> wrote in message
>
> news: oups.com...
>
> > what is the size of an class with not data members?
> > ex:
> > class A {
> > };
>
> > also
> > sizeof ?
> > class A{
> > int f(){
> > cout<<"Hello";
> > }
> > };
>
> Usually 1. Why don't you try it?

i've tried it... but why is it 1? Is it just for memory allocation so
that no two objects are allocated the same space?

<> wrote in message
news: oups.com...
> On Sep 5, 8:51 am, "Jim Langston" <tazmas...@rocketmail.com> wrote:
>> <deepakvs...@gmail.com> wrote in message
>>
>> news: oups.com...
>>
>> > what is the size of an class with not data members?
>> > ex:
>> > class A {
>> > };
>>
>> > also
>> > sizeof ?
>> > class A{
>> > int f(){
>> > cout<<"Hello";
>> > }
>> > };
>>
>> Usually 1. Why don't you try it?
>
> i've tried it... but why is it 1? Is it just for memory allocation so
> that no two objects are allocated the same space?

Yes, among other considerations.

On Sep 5, 9:43 am, "Jim Langston" <tazmas...@rocketmail.com> wrote:
> <deepakvs...@gmail.com> wrote in message
>
> news: oups.com...
>
>
>
>
>
> > On Sep 5, 8:51 am, "Jim Langston" <tazmas...@rocketmail.com> wrote:
> >> <deepakvs...@gmail.com> wrote in message
>
> >>news: groups.com...
>
> >> > what is the size of an class with not data members?
> >> > ex:
> >> > class A {
> >> > };
>
> >> > also
> >> > sizeof ?
> >> > class A{
> >> > int f(){
> >> > cout<<"Hello";
> >> > }
> >> > };
>
> >> Usually 1. Why don't you try it?
>
> > i've tried it... but why is it 1? Is it just for memory allocation so
> > that no two objects are allocated the same space?
>
> Yes, among other considerations.- Hide quoted text -
>
> - Show quoted text -

so you mean to say the actual size of object is 0 but it is allocated
atleast 1 byte..

On Sep 5, 5:54 am, "deepakvs...@gmail.com" <deepakvs...@gmail.com>
wrote:
> On Sep 5, 8:51 am, "Jim Langston" <tazmas...@rocketmail.com> wrote:
> > <deepakvs...@gmail.com> wrote in message

> >news: roups.com...

> > > what is the size of an class with not data members?
> > > ex:
> > > class A {
> > > };

> > > also
> > > sizeof ?
> > > class A{
> > > int f(){
> > > cout<<"Hello";
> > > }
> > > };

> > Usually 1. Why don't you try it?

It's implementation defined. It's usually 1 on byte addressed
machines, but probably the same as sizeof(int) on a word
addressed machine.

> i've tried it... but why is it 1? Is it just for memory allocation so
> that no two objects are allocated the same space?

It's principally so that no two objects (of the same type) have
the same address. If you write something like:
A array[2] ;
you are guaranteed that &array[0] != &array[1].

Note that there are certain, very special cases where the
compiler is allowed to allocate less memory than the size of the
object. For example, given:

class A {} ;
class B : public A { int i ;} ;

With many compilers, sizeof( B ) == sizeof( int ), even though
sizeof( A ) + sizeof( int ) is larger. (This is called the
"empty base class" optimization.)

--
James Kanze (GABI Software) email:
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<> wrote in message
news: ps.com...
> On Sep 5, 9:43 am, "Jim Langston" <tazmas...@rocketmail.com> wrote:
>> <deepakvs...@gmail.com> wrote in message
>>
>> news: oups.com...
>>
>> > On Sep 5, 8:51 am, "Jim Langston" <tazmas...@rocketmail.com> wrote:
>> >> <deepakvs...@gmail.com> wrote in message
>>
>> >>news: groups.com...
>>
>> >> > what is the size of an class with not data members?
>> >> > ex:
>> >> > class A {
>> >> > };
>>
>> >> > also
>> >> > sizeof ?
>> >> > class A{
>> >> > int f(){
>> >> > cout<<"Hello";
>> >> > }
>> >> > };
>>
>> >> Usually 1. Why don't you try it?
>>
>> > i've tried it... but why is it 1? Is it just for memory allocation so
>> > that no two objects are allocated the same space?
>>
>> Yes, among other considerations
>>
> so you mean to say the actual size of object is 0 but it is allocated
> atleast 1 byte..

No, the size of the object is 1 byte. The compiler adds a padding byte.
Read James message, an array of 0 sized objects wouldn't work.