What will be output of the code and why

[gaurav gupta]

#include <stdio.h>
#include <conio.h>
int main ()
{
printf ("%d\n",'-'-'-'-'/'/'/');
    getch();
}

//Can anyone explain the output of above code
 

--
GAURAV GUPTA
B.Tech IV Yr. , Department of Computer Science & Engineering
IT BHU , Varanasi
Contacts
Phone No: +91-99569-49491

e-mail :
gaurav...@acm.org
gaurav.gu...@itbhu.ac.in

[Shishir Mittal]

On Tue, Aug 11, 2009 at 11:13 PM, gaurav gupta <1989....@googlemail.com> wrote:

#include <stdio.h>
#include <conio.h>
int main ()
{
printf ("%d\n",'-'-'-'-'/'/'/');

This equivalent to printf("%d\n",45-45-47/47);

    getch();
}

//Can anyone explain the output of above code
 

--
GAURAV GUPTA
B.Tech IV Yr. , Department of Computer Science & Engineering
IT BHU , Varanasi
Contacts
Phone No: +91-99569-49491

e-mail :
gaurav...@acm.org
gaurav.gu...@itbhu.ac.in

--
Shishir Mittal
Ph: +91 9936 180 121

[gaurav gupta]

Great Mittal..........

Thanks.

[kinshuk chandra]

output is v.simple:
-1

because
'-' -'-'  is 0
and -'/' /  '/' is -1

because what here happening is that instead of '-' or '/' we have ascii value for these character values and rest operations are performed normally

On Tue, Aug 11, 2009 at 11:13 PM, gaurav gupta <1989....@googlemail.com> wrote:

--
Kinshuk Chandra
Senior Undergraduate
Computer Science and Engineering
IT-BHU
Contact No. (+91)9307134205
webpage: http://kinshuk.ram.googlepages.com/

[Gaurav Gupta]

printf("\n32<<-1 = %x 32<<-0=%x 32>>-1 = %x 32>>-0=%x",
32<<-1,32<<-0,32>>-1,32>>-0);

[Karan Jain]

Assuming integer size to be 32 bits, whenever you left or right shift a number with a negative count (except -0 which is actually 0), it automatically converts it to (32-count).

 

So, 32<<-1 = 32<<31  = 0 (0x00000000)

32<<-0 = 32<<0 = 32 (0x00000020)

32>>-1 = 32>>31 = 0 (0x00000000)

32>>-0 = 32>>0 = 32 (0x00000020)

 

Hence output should be:

 

32<<-1 = 0 32<<-0 = 20 32>>-1 = 0 32>>-0 = 20

--
Regards,

Karan

[gaurav gupta]

sorry for my misunderstanding I was interpreting the output as decimal number.

[Shishir Mittal]

On Fri, Aug 21, 2009 at 6:37 PM, Karan Jain <karanja...@gmail.com> wrote:

Assuming integer size to be 32 bits, whenever you left or right shift a number with a negative count (except -0 which is actually 0), it automatically converts it to (32-count).

Refer Pg 306, Dennis Ritchie. The result is undefined if the right operand is negative or greater than or equal to the number of bits in the left expression's type.

[Ajay]

In my book (The C Programming Language, 2nd Edition by K&R), there are only 272 pages (including index).

--
Ajay Kr. Gautam
IDD, Part V
Dept. of Computer Science & Engg., IT-BHU
Varanasi-221005, UP
India
-----------------------------------------------------------------
"Easy reading is damned hard writing."
~ Nathaniel Hawthorne

[Karan Jain]

11

11

kool

--
Regards,

Karan

[Shishir Mittal]

On Fri, Aug 21, 2009 at 7:55 PM, Ajay <ajay....@gmail.com> wrote:

In my book (The C Programming Language, 2nd Edition by K&R), there are only 272 pages (including index).

Sorry for the typo, its 206! or you may also refer pg 49.

[Ajay]

Well its implementation dependent like many other things.

For ex-

function argument execution is undefined in ANSI C but gcc follows right to left associativity.