little endian or big endian ???

[guthena]

Write a small C program to determine whether a machine's type is
little-endian or big-endian.

[CBFalconer]

Walter Roberson wrote:

>

.... snip ...

>
Take an unsigned integral type. C promises no internal padding
and no trap representations . Initialize it. Take its address and
cast the address to unsigned char pointer. C defines this
transformation as being possible and that the resulting unsigned
chars will each have no internal non-value bits and no trap
representations . ....

Nonsense.

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cbfalconer at maineline dot net

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[Walter Roberson]

In article <46************ ***@yahoo.com>,
CBFalconer <cb********@mai neline.netwrote :

>Walter Roberson wrote:

>Take an unsigned integral type. C promises no internal padding
and no trap representations . Initialize it. Take its address and
cast the address to unsigned char pointer. C defines this
transformati on as being possible and that the resulting unsigned
chars will each have no internal non-value bits and no trap
representation s. ....

>Nonsense.

Hmm? Which part is nonsense? Is it the part of C89 3.3 Expressions
that says, "An object shall have its stored value accessed only
by an lvalue that has one of the following types:
[...] - a character type" ?
--
If you lie to the compiler, it will get its revenge. -- Henry Spencer

[CBFalconer]

Walter Roberson wrote:

CBFalconer <cb********@mai neline.netwrote :

>Walter Roberson wrote:

>>Take an unsigned integral type. C promises no internal padding
and no trap representations . Initialize it. Take its address and
cast the address to unsigned char pointer. C defines this
transformatio n as being possible and that the resulting unsigned
chars will each have no internal non-value bits and no trap
representatio ns. ....

>Nonsense.

Hmm? Which part is nonsense? Is it the part of C89 3.3 Expressions
that says, "An object shall have its stored value accessed only
by an lvalue that has one of the following types:
[...] - a character type" ?

I think the following quote (from N869) is adequate:

6.2.6.2 Integer types

[#1] For unsigned integer types other than unsigned char,
the bits of the object representation shall be divided into
two groups: value bits and padding bits (there need not be
any of the latter). If there are N value bits, each bit
shall represent a different power of 2 between 1 and 2N-1,
so that objects of that type shall be capable of
representing values from 0 to 2N-1 using a pure binary
representation; this shall be known as the value
representation. The values of any padding bits are
unspecified.39)

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<http://www.securityfoc us.com/columnists/423>
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cbfalconer at maineline dot net
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[Richard Bos]

Spade <st***********@ gmail.comwrote:

On Jun 29, 3:22 pm, [e-mail] (Richard Bos) wrote:

Tejas Kokje <binarysemaph.. [e-mail] e:

On Jun 28, 12:01 pm, guthena <r4r...@gmail.c omwrote:
Write a small C program to determine whether a machine's type is
little-endian or big-endian.

Here you go..

int main()
{
int num=1;
char *cptr;

cptr = (char *)&num;

if (*cptr)
printf ("little endian\n");
else
printf ("big endian\n");

return 0;
}

Which company interview question is this ? :-D

Congratulations . You just did his homework for him. Since it's a crappy
assignment,

This most probably isn't a homework question. Its a typical question
thats asked mostly in interviews in India.

It's also a typical question that's asked in many badly thought out
computing courses.

his teacher probably thinks he did a sterling job, he'll
probably pass the course on the back of your work, and he'll end up
holding a job as a programmer _still_ thinking that this is a good
program. Which it is not; it is flawed for several reasons.

Can you tell me how it is flawed?

I can, but I won't. The whole exercise is a wild goose chase, and I'm
not going to help you by telling you which other wild species of goose
you could chase. That would only make a futile pursuit differently
futile, not less.

Richard