memset o/p not correct

**aarklon@gmail.com** · Jun 27 '08, 07:30 PM

Re: memset o/p not correct

sorry I forgot to declare i , but still the o/p is same

#include <string.h>
#include <stdio.h>
#include <stdlib.h>

int main(void)
{

int maxpat[80],i;
memset(maxpat,-1,80);

for(i=0;i<80;i+ +)
printf("%d\t",m axpat[i]);

return EXIT_SUCCESS;
}

**aarklon@gmail.com** · Jun 27 '08, 07:30 PM

Re: memset o/p not correct

On Apr 20, 2:28 am, aark...@gmail.c om wrote:

Hi,
>
the following is actually a part of the pattern matching program which
i tried ,memset is not setting the entire integer array with
-1
>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
>
int main(void)
{
>
int maxpat[80];
memset(maxpat,-1,80);
>
for(i=0;i<80;i+ +)
printf("%d\t",m axpat[i]);
>
return EXIT_SUCCESS;
}
>
but i am getting o/p as
>
-1 -1 -1 -1 -1 -1 -1 -1
-1 -1
-1 -1 -1 -1 -1 -1 -1 -1
-1 -1
-370086 -370086 -370086 -370086 -370086 -370086 -370086 -370086
-370086 -370086
-370086 -370086 -370086 -370086 -370086 -370086 -370086 -370086
-370086 -370086
-370086 -370086 -370086 -370086 -370086 -370086 -370086 -370086
-370086 -370086
-370086 -370086 -370086 -370086 -370086 -370086 -370086 -370086
-370086 -370086
-370086 -370086 -370086 -370086 -370086 -370086 -370086 -370086
-370086 -370086
-370086 -370086 -370086 -370086 -370086 -370086 -370086 -370086
-370086 -370086
>
"D:\siju\lcc6\n oisedisp.exe"
Return code 0
Execution time 0.048 seconds
Press any key to continue...
>
why is this so..????

sorry I forgot to declare i, but still the o/p is same

**Ian Collins** · Jun 27 '08, 07:30 PM

Re: memset o/p not correct

aarklon@gmail.c om wrote:

Hi,
>
the following is actually a part of the pattern matching program which
i tried ,memset is not setting the entire integer array with
-1
>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
>
int main(void)
{
>
int maxpat[80];
memset(maxpat,-1,80);
>

You are only setting the first 80 bytes of the the array, not 80 ints.

--
Ian Collins.

**Bartc** · Jun 27 '08, 07:30 PM

Re: memset o/p not correct

<aarklon@gmail. comwrote in message
news:c7633ee9-954f-4ad8-a0c0-646fbe8e8e81@b5 g2000pri.google groups.com...

Hi,
>
the following is actually a part of the pattern matching program which
i tried ,memset is not setting the entire integer array with
-1
>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
>
int main(void)
{
>
int maxpat[80];
memset(maxpat,-1,80);

You're setting 80 bytes. The array is bigger than that (80*sizeof(int) ).
Try:

memset(maxpat,-1,sizeof maxpat);

--
Bart

**Flash Gordon** · Jun 27 '08, 07:30 PM

Re: memset o/p not correct

aarklon@gmail.c om wrote, On 19/04/08 22:31:

sorry I forgot to declare i , but still the o/p is same
>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
>
int main(void)
{
int maxpat[80],i;
memset(maxpat,-1,80);

<snip>

Check the definition of memset in your reference book, it sets a
specified number of *bytes*. This also means that having corrected the
error (sizeof *maxpat is your friend) it won't be portable to
implementations using 1s complement or sign-magnitude if you can find
such an implementation.
--
Flash Gordon

**Default User** · Jun 27 '08, 07:30 PM

Re: memset o/p not correct

aarklon@gmail.c om wrote:

Hi,
>
the following is actually a part of the pattern matching program which
i tried ,memset is not setting the entire integer array with
-1

int maxpat[80];
memset(maxpat,-1,80);

As the others have pointed out, it sets each byte to the value. There's
almost no way to do what you want with memset(), unless you happen to
be on a machine that had one-byte ints.

To set each int in the array to -1, you need a loop. Better yet,
explain WHY you want to do this. There may be a better construct.

Brian

**Richard Tobin** · Jun 27 '08, 07:30 PM

Re: memset o/p not correct

In article <66vedbF2m6h5lU 1@mid.individua l.net>,
Default User <defaultuserbr@ yahoo.comwrote:

> int maxpat[80];
> memset(maxpat,-1,80);

>As the others have pointed out, it sets each byte to the value. There's
>almost no way to do what you want with memset(), unless you happen to
>be on a machine that had one-byte ints.

Unless you really on the machines being 2s-complement, which is true
of all general-purpose computers today.

-- Richard
--
:wq

**Richard** · Jun 27 '08, 07:30 PM

Re: memset o/p not correct

"Default User" <defaultuserbr@ yahoo.comwrites :

aarklon@gmail.c om wrote:
>

>Hi,
>>
>the following is actually a part of the pattern matching program which
>i tried ,memset is not setting the entire integer array with
>-1

>

> int maxpat[80];
> memset(maxpat,-1,80);

>
As the others have pointed out, it sets each byte to the value. There's
almost no way to do what you want with memset(), unless you happen to
be on a machine that had one-byte ints.
>
To set each int in the array to -1, you need a loop. Better yet,
explain WHY you want to do this. There may be a better construct.

I would be interested to hear how you knowing WHY he needs to set a
sequence of ints to a single value would in any way "optimise" your
advice.

>
>
>
Brian

**CBFalconer** · Jun 27 '08, 07:30 PM

Re: memset o/p not correct

Richard Tobin wrote:

Default User <defaultuserbr@ yahoo.comwrote:
>

>> int maxpat[80];
>> memset(maxpat,-1,80);

>

>As the others have pointed out, it sets each byte to the value.
>There's almost no way to do what you want with memset(), unless
>you happen to be on a machine that had one-byte ints.

>
Unless you really on the machines being 2s-complement, which is
true of all general-purpose computers today.

What's the point of the foolishness, when:

#define MPSIZE 80
#define VALUE -1
int maxpat[MPSIZE], i;

for (i = 0; i < MPSIZE; i++) maxpat[i] = VALUE;

handles it accurately and portably, doesn't care about what VALUE
is, and preserves the value of MPSIZE for any other uses. Note
that the bit of code above doesn't have to be in the scope of
maxpat, rather it can receive it as a parameter.

--
[mail]: Chuck F (cbfalconer at maineline dot net)
[page]: <http://cbfalconer.home .att.net>
Try the download section.

** Posted from http://www.teranews.com **

**Willem** · Jun 27 '08, 07:30 PM

Re: memset o/p not correct

Richard wrote:
) In article <66vedbF2m6h5lU 1@mid.individua l.net>,
) Default User <defaultuserbr@ yahoo.comwrote:
)
)> int maxpat[80];
)> memset(maxpat,-1,80);
)
)>As the others have pointed out, it sets each byte to the value. There's
)>almost no way to do what you want with memset(), unless you happen to
)>be on a machine that had one-byte ints.
)
) Unless you really on the machines being 2s-complement, which is true
) of all general-purpose computers today.

And then he wants to set the entire array to -2 instead.

SaSW, Willem
--
Disclaimer: I am in no way responsible for any of the statements
made in the above text. For all I know I might be
drugged or something..
No I'm not paranoid. You all think I'm paranoid, don't you !
#EOT

**Keith Thompson** · Jun 27 '08, 07:30 PM

Re: memset o/p not correct

CBFalconer <cbfalconer@yah oo.comwrites:
[...]

#define MPSIZE 80
#define VALUE -1
int maxpat[MPSIZE], i;
>
for (i = 0; i < MPSIZE; i++) maxpat[i] = VALUE;

[...]

Quibble:
#define VALUE (-1)
It doesn't matter in this case, but it's a good habit.

--
Keith Thompson (The_Other_Keit h) <kst-u@mib.org>
Nokia
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"

**Ian Collins** · Jun 27 '08, 07:30 PM

Re: memset o/p not correct

Keith Thompson wrote:

CBFalconer <cbfalconer@yah oo.comwrites:
[...]

> #define MPSIZE 80
> #define VALUE -1
> int maxpat[MPSIZE], i;
>>
> for (i = 0; i < MPSIZE; i++) maxpat[i] = VALUE;

[...]
>
Quibble:
#define VALUE (-1)
It doesn't matter in this case, but it's a good habit.
>

Better still

const int value = -1;

--
Ian Collins.

**CBFalconer** · Jun 27 '08, 07:30 PM

Re: memset o/p not correct

Ian Collins wrote:

Keith Thompson wrote:

>CBFalconer <cbfalconer@yah oo.comwrites:
>>
>[...]
>>

>> #define MPSIZE 80
>> #define VALUE -1
>> int maxpat[MPSIZE], i;
>>>
>> for (i = 0; i < MPSIZE; i++) maxpat[i] = VALUE;

>[...]
>>
>Quibble:
> #define VALUE (-1)
>>
>It doesn't matter in this case, but it's a good habit.

>
Better still
>
const int value = -1;

The quibble is fine, but this last is a horror. We want a
constant, not a pre-initialized int. If you want c++, use the
appropriate newsgroup.

--
[mail]: Chuck F (cbfalconer at maineline dot net)
[page]: <http://cbfalconer.home .att.net>
Try the download section.

** Posted from http://www.teranews.com **

**Ian Collins** · Jun 27 '08, 07:30 PM

Re: memset o/p not correct

CBFalconer wrote:

Ian Collins wrote:

>Keith Thompson wrote:

>>CBFalconer <cbfalconer@yah oo.comwrites:
>>>
>>[...]
>>>
>>> #define MPSIZE 80
>>> #define VALUE -1
>>> int maxpat[MPSIZE], i;
>>>>
>>> for (i = 0; i < MPSIZE; i++) maxpat[i] = VALUE;
>>[...]
>>>
>>Quibble:
>> #define VALUE (-1)
>>>
>>It doesn't matter in this case, but it's a good habit.

>Better still
>>
>const int value = -1;

>
The quibble is fine, but this last is a horror. We want a
constant, not a pre-initialized int. If you want c++, use the
appropriate newsgroup.
>

I think you've topped your own stupidity this time.

--
Ian Collins.

memset o/p not correct

memset o/p not correct

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