GATECSE - User contributions [en]

MediaWiki:Userlogin

2014-02-27T15:01:57Z

Arjun:

Log in / create account

You can also <span class="mw-facebook-logo">[[Special:Connect|log in with Facebook]]</span>. <fb:login-button show-faces="false" width="450" max-rows="1" scope="auto"></fb:login-button><br/><br/>

MediaWiki:Userlogin

2014-02-27T15:01:36Z

Arjun:

Log in / create account

You can also <span class="mw-facebook-logo">[[Special:Connect|log in with Facebook]]</span>. <fb:login-button show-faces="true" width="450" max-rows="1" scope="auto"></fb:login-button><br/><br/>

MediaWiki:Userlogin

2014-02-27T15:01:28Z

Arjun: Created page with "Log in / create account You can also <span class="mw-facebook-logo">log in with Facebook</span>. <fb:login-button show-faces="true" width="450" max-rows="1..."

Log in / create account
You can also <span class="mw-facebook-logo">[[Special:Connect|log in with Facebook]]</span>. <fb:login-button show-faces="true" width="450" max-rows="1" scope="auto"></fb:login-button><br/><br/>

MediaWiki:Login

2014-02-27T15:00:12Z

Arjun: Replaced content with "Log in"

MediaWiki:Login

2014-02-27T14:58:52Z

Arjun: Created page with "You can also <span class="mw-facebook-logo">log in with Facebook</span>. <fb:login-button show-faces="true" width="450" max-rows="1" scope="auto"></fb:lo..."

You can also <span class="mw-facebook-logo">[[Special:Connect|log in with Facebook]]</span>.

<fb:login-button show-faces="true" width="450" max-rows="1" scope="auto"></fb:login-button><br/><br/>

Category:Programming

2013-12-06T17:47:38Z

Arjun:

[http://www.compileonline.com/ Compile code online]

[[Category:Technical]]

User:Arjun Suresh

2013-12-04T10:41:10Z

Arjun:

[http://armi.in/arjun Arjun Suresh]

User:Arjun Suresh

2013-12-04T10:40:56Z

Arjun: Created page with "[http://armi.in/arjun]"

[http://armi.in/arjun]

File:Keycs 2012.pdf

2013-12-04T10:29:47Z

Arjun: Arjun moved page File:Keycs 2012.pdf to File:Key CS 2012.pdf

#REDIRECT [[File:Key CS 2012.pdf]]

File:Key CS 2012.pdf

2013-12-04T10:29:47Z

Arjun: Arjun moved page File:Keycs 2012.pdf to File:Key CS 2012.pdf

Using git

2013-12-02T22:55:30Z

Arjun:

<metadesc>How to start using git</metadesc>

*Initializes a git repository on the current folder
git init

*Add a remote git repository
git remote add <name> <url>

*Fetches a remote git branch
git pull <name> serverbranch:localbranch

*Adds a new file to git
git add <filename>

*Saves the new changes to the git branch(local)
git commit -m "<commit message>"

*Pushes the local branch to the server
git push <name> localbranch:serverbranch

*Switches to a new branch
git checkout <branchname>

*Creates and switches to a new branch
git checkout -b <branchname>

*See all the merges
git branch

*Merges a branch with the current branch
git merge <branchname>

<div class="fb-like" data-layout="standard" data-action="like" data-show-faces="false" data-share="true"></div>

<div class="fb-share-button" data-type="button_count"></div>

<disqus/>

[[Category:Technical]]

Using git

2013-12-02T22:55:17Z

Arjun:

Using git

2013-12-02T22:54:45Z

Arjun:

Using git

2013-12-02T22:54:21Z

Arjun:

Using git

2013-12-02T21:55:18Z

Arjun:

Using git

2013-12-02T21:47:01Z

Arjun: Created page with "<metadesc>How to start using git</metadesc> *git init *git remote add <name> <url> *git pull <name> serverbranch:localbranch *git-push <name> localbranch:serverbranch ..."

<metadesc>How to start using git</metadesc>

*git init

*git remote add <name> <url>

*git pull <name> serverbranch:localbranch

*git-push <name> localbranch:serverbranch

[[Category:Technical]]

Useful Technical Tools

2013-12-01T19:31:41Z

Arjun:

<metadesc>Some useful online tools like for editing latex documents, drawing ER diagrams/flowcharts, compiling code online etc.</metadesc>
* [http://mathurl.com/ Latex symbols]

* [https://www.sharelatex.com?r=cc1bd49f&rm=d&rs=b Online LaTeX Editor]

* [http://lucidchart.com Draw diagrams online]
* [http://www.compileonline.com/ Compile codes online]

<div class="fb-like" data-layout="standard" data-action="like" data-show-faces="true" data-share="true"></div>

<div class="fb-share-button" data-type="button_count"></div>

[[Category: Technical]]

Main Page

2013-12-01T19:29:55Z

Arjun:

<metadesc>ARMI wiki contains information related to Life in France as an Indian, doing PhD in INRIA, France, Tips and materials for GATE preparation in Computer Science stream and some other useful technical and non-technical articles</metadesc>
=ARMI wiki=
Welcome to ARMI wiki. This wiki contains information on the following categories
* [https://armi.in/wiki/Category:France France]: For sharing information on life in France as an Indian

* [https://armi.in/wiki/Category:Rennes Rennes]: Coming to Rennes, France as a PhD student

* [https://armi.in/wiki/Category:GATE GATE]: For helping Computer Science and Engineering Students to prepare for GATE

* [https://armi.in/wiki/Category:Code Code]: Programming Codes

* [https://armi.in/wiki/Category:Technical Technical]: Some useful technical tips in Computers

* [https://armi.in/wiki/Category:Articles Articles]: Non-Technical Articles

<div class="fb-like" data-layout="standard" data-action="like" data-show-faces="false" data-share="true"></div>

<div class="fb-share-button" data-type="button_count"></div>

Category:Rennes

2013-12-01T16:10:27Z

Arjun:

<metadesc>Coming and settling in Rennes, France. Things to know in Rennes.</metadesc>
Rennes is a city in the east of Brittany in northwestern France. Rennes is the capital of the region of Brittany, as well as the Ille-et-Vilaine department.

[Courtesy: [http://en.wikipedia.org/wiki/Rennes Wikipedia]]

<div class="fb-like" data-layout="standard" data-action="like" data-show-faces="false" data-share="true"></div>

<div class="fb-share-button" data-type="button_count"></div>

[[Category:France]]

Category:France

2013-12-01T15:57:00Z

Arjun:

<metadesc>Information about coming and living in France especially from an Indian point of view.
</metadesc>
This page contains links to some useful stuffs about coming and living in France especially from an Indian point of view.
=Life in France=
France is a developed country and the standard of living is quite high. Living expense is quite high but is less than the likes of Switzerland and all. French government provides good support for research and the social security in France is quite good. French people are also very friendly (not as much as Spanish) but if you don't speak French it's difficult to interact socially.

French people are not at all racist. In all offices they don't consider anyone as outsider- especially if you speak French. And in most of the Government offices in France service is much much better than in India- they promptly reply to emails, take photocopies for customer documents etc. French people do enjoy their life. they have like 40 days vacation every year and they don't work outside office hours. i.e.; they mostly work from 6-9 and thereafter don't work. And they do take a good lunch break also. But during their work hours they are as dedicated as any- that shows in their achievements.

Other thing special about French is that they do have good family relationships. At many tourist places you can see couples, including many old ones, coming and enjoying their life. Even in cities you can find a lot of families roaming around.

Since people from many countries come to France, take care of your stuffs while travelling. Many pickpockets and baggage loses happen in France, especially Paris.

=Should I know French=
For most of the French people French is the only language they need to know. Everything in France is in French- from advertising boards, newspapers, TV channels and even computer keyboards. So, if you need anything in English it should be specially obtained. And you won't be able to find many people in France speaking English fluently. It's because their accent is completely different.

If you're doing an English course, then you can manage without learning French [http://translate.google.com Google translate] is always there. But, if you want to mingle with locals or to obtain a job outside an English speaking organization you should definitely know French.

<div class="fb-like" data-layout="standard" data-action="like" data-show-faces="false" data-share="true"></div>

<div class="fb-share-button" data-type="button_count"></div>

--[[User:Arjun|Arjun]] ([[User talk:Arjun|talk]]) 22:54, 16 November 2013 (UTC)

Dining Philosopher with Threads Implementation in C/C++

2013-12-01T15:47:49Z

Arjun:

<metadesc>C implementation of dining philosophers problem with threads</metadesc>
<syntaxhighlight lang="c">
//Dining philosopher using threads

#include<stdio.h>
#include<pthread.h>

void* reader(void*);
pthread_mutex_t mut[5];
int n;

int main()
{
pthread_t t1[5];
int i,j=0,k;
n = 5;
for(i=0;i<n;i++)
{
j=i;
pthread_create(&t1[i],NULL,reader,&j);
}
for(j=0;j<n;j++)
pthread_join(t1[j],NULL);
return 1;
}

void *reader(void* arg)
{
int val=*(int*)arg;
printf("%d Thinking\n",val+1);
pthread_mutex_lock(&mut[val%n]);
pthread_mutex_lock(&mut[(val+1)%n]);
printf("%d Eating\n",val+1);
sleep(3);
pthread_mutex_unlock(&mut[val%n]);
pthread_mutex_unlock(&mut[(val+1)%n]);
printf("%d Finished Eating\n",val+1);
}
</syntaxhighlight>

<div class="fb-like" data-layout="standard" data-action="like" data-show-faces="false" data-share="true"></div>

<div class="fb-share-button" data-type="button_count"></div>

[[Category: Operating System Codes]]

Category:Operating System Codes

2013-12-01T15:46:53Z

Arjun:

<metadesc>C code for implementing basic Operating System functions</metadesc>
C code for implementing basic Operating System functions
[[Category:Code]]

<div class="fb-like" data-layout="standard" data-action="like" data-show-faces="false" data-share="true"></div>

<div class="fb-share-button" data-type="button_count"></div>

Category:Operating System Codes

2013-12-01T15:46:14Z

Arjun:

<metadesc>C code for implementing basic Operating System functions</metadesc>
[[Category:Code]]

<div class="fb-like" data-layout="standard" data-action="like" data-show-faces="false" data-share="true"></div>

<div class="fb-share-button" data-type="button_count"></div>

Category:Operating System Codes

2013-12-01T15:45:47Z

Arjun:

<metadesc>C code for implementing basic Operating System functions</metadesc>
[[Category:Code]]

SSH without Password

2013-12-01T15:40:05Z

Arjun:

<metadesc>How to SSH without password to server</metadesc>
The basis of this is that your ID must be in the list of authorized hosts in the server. So, for password-less login to work, generate your public key, and append it to the authorized_hosts file in the server.
<div class="like-box" data-href="http://www.facebook.com/FacebookDevelopers" data-colorscheme="light" data-show-faces="true" data-header="true" data-stream="false" data-show-border="true"></div>
*To create a public key, from terminal do
ssh-keygen -t rsa
*To copy to authorized_hosts file do
cat ~/.ssh/id_rsa.pub | ssh serveruser@server 'cat >> ~/.ssh/authorized_keys'

Test by
ssh serveruser@server

If no password is asked, everything worked fine.

You can also do the following command to copy the key
ssh-copy-id serveruser@server

<div class="fb-like" data-layout="standard" data-action="like" data-show-faces="true" data-share="true"></div>

<div class="fb-share-button" data-type="button_count"></div>

<disqus/>

[[Category:Technical]]

Moving Negative Numbers to the Beginning of Array

2013-12-01T15:34:49Z

Arjun:

Makes the positive numbers appear after the negative numbers in an array.

Complexity <math>\theta(n)</math>

No. of swaps in the worst case = <math> \lfloor n/2 \rfloor</math>

<syntaxhighlight lang="c">
#include<stdio.h>
int main()
{
int i, n, pi, ni, count = 0;
int a[1000];
printf("Enter size of array: ");
scanf("%d",&n);
printf("Enter numbers of array\n");
for(i=0; i<n; i++)
{
scanf("%d",&a[i]);
}
ni = n-1;
while(a[ni] >= 0)
ni--;
pi = 0;
while(a[pi] < 0)
pi++;
while(ni > pi)
{
int temp = a[pi];
a[pi] = a[ni];
a[ni] = temp;
while(a[ni] >= 0)
ni--;
while(a[pi] < 0)
pi++;

}

for(i=0; i<n; i++)
{
printf("%d ", a[i]);
}

}
</syntaxhighlight>

<div class="fb-like" data-layout="standard" data-action="like" data-show-faces="false" data-share="true"></div>

<div class="fb-share-button" data-type="button_count"></div>

<disqus></disqus>

[[Category:Arrays]]

Category:Code

2013-12-01T15:30:20Z

Arjun:

Programs

[http://www.compileonline.com/ Compile code online]

Useful Technical Tools

2013-12-01T15:29:39Z

Arjun:

* [http://mathurl.com/ Latex symbols]

* [https://www.sharelatex.com?r=cc1bd49f&rm=d&rs=b Online LaTeX Editor]

* [http://lucidchart.com Draw diagrams online]
* [http://www.compileonline.com/ Compile codes online]

<div class="fb-like" data-layout="standard" data-action="like" data-show-faces="true" data-share="true"></div>

<div class="fb-share-button" data-type="button_count"></div>

[[Category: Technical]]

Cache Memory

2013-12-01T14:06:58Z

Arjun:

<metadesc>Cache memory organization in Processors </metadesc>
[http://csillustrated.berkeley.edu/PDFs/handouts/cache-3-associativity-handout.pdf Handout from Berkeley]

[http://download.intel.com/design/intarch/papers/cache6.pdf Cache Organization by Intel]

[[Category:Computer Architecture]]

Cache Memory

2013-12-01T14:06:49Z

Arjun:

<metadesc>Cache memory organization in Processors </metadesc>

[http://csillustrated.berkeley.edu/PDFs/handouts/cache-3-associativity-handout.pdf Handout from Berkeley]

[http://download.intel.com/design/intarch/papers/cache6.pdf Cache Organization by Intel]

[[Category:Computer Architecture]]

Cache Memory

2013-12-01T14:05:52Z

Arjun: Arjun moved page Associativity of Caches to Cache Memory

[http://csillustrated.berkeley.edu/PDFs/handouts/cache-3-associativity-handout.pdf Handout from Berkeley]

[http://download.intel.com/design/intarch/papers/cache6.pdf Cache Organization by Intel]

[[Category:Computer Architecture]]

Associativity of Caches

2013-12-01T14:05:52Z

Arjun: Arjun moved page Associativity of Caches to Cache Memory

#REDIRECT [[Cache Memory]]

Cache Memory

2013-12-01T14:05:31Z

Arjun:

Cache Memory

2013-12-01T14:05:19Z

Arjun:

Category:Computer Networks

2013-12-01T12:04:14Z

Arjun: Created page with "Category:GATE"

[[Category:GATE]]

Cache Memory

2013-12-01T11:55:39Z

Arjun:

[http://csillustrated.berkeley.edu/PDFs/handouts/cache-3-associativity-handout.pdf Handout from Berkeley]

[[Category:Computer Architecture]]

Cache Memory

2013-12-01T11:55:18Z

Arjun: Created page with "[http://csillustrated.berkeley.edu/PDFs/handouts/cache-3-associativity-handout.pdf] Category:Computer Architecture"

[http://csillustrated.berkeley.edu/PDFs/handouts/cache-3-associativity-handout.pdf]

[[Category:Computer Architecture]]

My GATE Experience

2013-11-30T01:44:02Z

Arjun:

<metadesc>My experience of GATE preparation, how to prepare for GATE</metadesc>
=My GATE Experience=
==Preparation==
While during B.Tech as any normal student I also wanted to write GATE. As a natural step I thought of coaching. But due to lack of good coaching centers nearby, I didn't join any. Instead, bought GATE forum materials. I tried to solve their questions, but couldn't proceed more than 2 pages as they were qite tough for me. So, thinking GATE is another dream I won't be able to reach, I left my GATE desire and decided to go for placement, which was a rather easy choice.

==Expectation==
I had spent hours for studying during my +2. I studied in a very good school and took the best tuition classes in my city. My entrance score was good enough to get me a seat in the best engineering college of the state, but I couldn't answer even 1 question with confidence during IIT-JEE. Now, I'm in a government engineering college without proper teachers in any semesters (teachers were either transferred every year or they went for higher studies), no lecture notes, and no competition for ranks in the class. Moreover, the time I spent studying during B.Tech is no where comparable to that I spent for during my Engineering entrance. In such a situation, I couldn't even dream of cracking GATE. So, I never bothered to check how GATE exam is. All I knew was that GATE is for 3 hours and it contains 65 MCQs.

==Exam==
Still I wrote GATE just to see how it is. I hadn't seen even 1 previous year GATE question paper. My only aim was not to get disqualified (I heard from somewhere that there's a disqualification mark for it). Exam started. I was happy as I could attempt some questions.

==Result==
Results came. My rank was 330 out of more than 107,000 candidates. I couldn't imagine how it could have happened. Were the other candidates worse than me?

==What all went wrong?==
Now, when I think of what all helped me during GATE, following points come to my mind:

#In B.Tech we hardly had any lectures. So, we were forced to study by ourselves. As one of our lecturer told us, the most important thing our college teaches us is to learn on our own. (She studied in that college only). And the advantage of learning by ourselves is that we can crack most questions even if it's twisted.
#I was following some printed notes and local textbooks till semester 4. My GPA wasn't bad but I never learned anything. During S5 someone told us to buy standard textbooks which were prescribed in the syllabus. I gave it a try. My GPA remained same but I was happy because I felt like I learned something. Moreover, whatever I learned from those books still remain with me.
#Though quite lazy, I used to do all the lab assignments. I never referred any previous code in doing any assignment as I preferred to write my own code. Did this help in GATE? - Yes, I could write all the questions in C, DS & algorithm and DBMS in GATE with 100% confidence. (Unfortunately, we had OS lab only after GATE exam).
#I was quite poor in Engineering Mathematics. I was following a local textbook for it as I thought why I needed to learn Mathematics to become a Software Engineer. So, I couldn't answer most of the Mathematics questions in GATE. Due to lack of preparation, questions from OS, Networks and CO weren't easy for me also. Still, I could apply my logic, substitute answers from choices and solve many of them.
#Due to lack of coaching, I didn't know any method to solve any GATE question. So, I had to use just my limited knowledge and logic to solve them. Still, I was able to solve more than half of the questions as they were just testing the basic subject knowledge. During IIT-JEE I was trained in solving entrance questions. But, during exam, I couldn't attempt any. The coaching had made the problem solving methods kind of hardcoded in my mind and I couldn't even understand any question outside that. This hardcoded problem solving methods were lacking for me in GATE and that helped me in solving many questions. With 180 minutes for 65 questions, I never felt the need for any shortcut methods also.

==A Caution==
My GATE mark was 53.66/100. Still, I could get into IISc due to OBC reservation and due to the fact that competition wasn't that tough in 2010. But now, to safely get into IITs/IISc, a mark of more than 70/100 is needed. It's very much possible for you. Don't study 10-12 hours a day. Study till you can, but do it properly. Enjoy whatever you learn. You can crack anything...

Please read the questions properly. I lost at least 10 marks in GATE, as I misread or misinterpreted the question.

<div class="fb-like" data-layout="standard" data-action="like" data-show-faces="false" data-share="true"></div>

<div class="fb-share-button" data-type="button_count"></div>

<disqus/>

[[Category:Articles]]
[[Category:GATE]]

Undefined Value

2013-11-30T01:04:40Z

Arjun:

<metadesc>Undefined value in C language, sequence point</metadesc>
<syntaxhighlight lang="c">
#include<stdio.h>
int main()
{
int x=10, y;
y = (x++) + (++x);
printf("%d %d %d %d ", y, x++, x, ++x);
}
</syntaxhighlight>

'''a)''' 22,10,11,13

'''b)''' 22,11,11,11

'''c)''' 12,10,11,13

'''d)''' 22 13 13 13

None of the choices are correct as per [http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1124.pdf C standard]. This is because the statement
y = (x++) + (++x);

can causes undefined behavior, so does the statement
printf("%d %d %d %d ", y, x++, x, ++x);

C standard says that the side effects of an operation (for b = ++a; modification of a is a side-effect) need to be completed only before the next [https://en.wikipedia.org/wiki/Sequence_point sequence point]. This relaxation is given so that the compiler would be able to generate the most optimal code (which run faster). But as a consequence, programmer shouldn't do a read and a write from a memory location within a sequence point or otherwise the result would be undefined.

In the statement,
y = (x++) + (++x);

There are 2 reads to the memory location of x and 2 writes to the same within a sequence point. So, the result of this statement has no guarantee as per C standard.

Similarly, the statement
printf("%d %d %d %d ", y, x++, x, ++x);

is undefined. In a function call in C, the arguments are pushed onto the stack from right to left (the left most argument would be on top of the stack, so that variable no. of arguments can work in C). But the order in which the argument expressions are processed is not defined. The only thing defined is that all arguments must be processes before the next sequence point- which here is the execution of the called function.

I have seen many people saying C is so stupid because of these undefined behaviors. But that's the power of C. A programmer in C should know about these behaviors and avoid writing undefined codes.

<div class="fb-like" data-layout="standard" data-action="like" data-show-faces="false" data-share="true"></div>

<div class="fb-share-button" data-type="button_count"></div>

<disqus/>

[[Category:Code]]

Undefined Value

2013-11-30T01:04:24Z

Arjun:

<metadesc>Undefined value in C language, sequence point</metadesc>

<syntaxhighlight lang="c">
#include<stdio.h>
int main()
{
int x=10, y;
y = (x++) + (++x);
printf("%d %d %d %d ", y, x++, x, ++x);
}
</syntaxhighlight>

'''a)''' 22,10,11,13

'''b)''' 22,11,11,11

'''c)''' 12,10,11,13

'''d)''' 22 13 13 13

None of the choices are correct as per [http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1124.pdf C standard]. This is because the statement
y = (x++) + (++x);

can causes undefined behavior, so does the statement
printf("%d %d %d %d ", y, x++, x, ++x);

C standard says that the side effects of an operation (for b = ++a; modification of a is a side-effect) need to be completed only before the next [https://en.wikipedia.org/wiki/Sequence_point sequence point]. This relaxation is given so that the compiler would be able to generate the most optimal code (which run faster). But as a consequence, programmer shouldn't do a read and a write from a memory location within a sequence point or otherwise the result would be undefined.

In the statement,
y = (x++) + (++x);

There are 2 reads to the memory location of x and 2 writes to the same within a sequence point. So, the result of this statement has no guarantee as per C standard.

Similarly, the statement
printf("%d %d %d %d ", y, x++, x, ++x);

is undefined. In a function call in C, the arguments are pushed onto the stack from right to left (the left most argument would be on top of the stack, so that variable no. of arguments can work in C). But the order in which the argument expressions are processed is not defined. The only thing defined is that all arguments must be processes before the next sequence point- which here is the execution of the called function.

I have seen many people saying C is so stupid because of these undefined behaviors. But that's the power of C. A programmer in C should know about these behaviors and avoid writing undefined codes.

<div class="fb-like" data-layout="standard" data-action="like" data-show-faces="false" data-share="true"></div>

<div class="fb-share-button" data-type="button_count"></div>

<disqus/>

[[Category:Code]]

Undefined Value

2013-11-30T00:55:45Z

Arjun:

<syntaxhighlight lang="c">
#include<stdio.h>
int main()
{
int x=10, y;
y = (x++) + (++x);
printf("%d %d %d %d ", y, x++, x, ++x);
}
</syntaxhighlight>

'''a)''' 22,10,11,13

'''b)''' 22,11,11,11

'''c)''' 12,10,11,13

'''d)''' 22 13 13 13

None of the choices are correct as per [http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1124.pdf C standard]. This is because the statement
y = (x++) + (++x);

can causes undefined behavior, so does the statement
printf("%d %d %d %d ", y, x++, x, ++x);

C standard says that the side effects of an operation (for b = ++a; modification of a is a side-effect) need to be completed only before the next [https://en.wikipedia.org/wiki/Sequence_point sequence point]. This relaxation is given so that the compiler would be able to generate the most optimal code (which run faster). But as a consequence, programmer shouldn't do a read and a write from a memory location within a sequence point or otherwise the result would be undefined.

In the statement,
y = (x++) + (++x);

There are 2 reads to the memory location of x and 2 writes to the same within a sequence point. So, the result of this statement has no guarantee as per C standard.

Similarly, the statement
printf("%d %d %d %d ", y, x++, x, ++x);

is undefined. In a function call in C, the arguments are pushed onto the stack from right to left (the left most argument would be on top of the stack, so that variable no. of arguments can work in C). But the order in which the argument expressions are processed is not defined. The only thing defined is that all arguments must be processes before the next sequence point- which here is the execution of the called function.

I have seen many people saying C is so stupid because of these undefined behaviors. But that's the power of C. A programmer in C should know about these behaviors and avoid writing undefined codes.

<div class="fb-like" data-layout="standard" data-action="like" data-show-faces="false" data-share="true"></div>

<div class="fb-share-button" data-type="button_count"></div>

<disqus/>

[[Category:Code]]

Undefined Value

2013-11-30T00:54:58Z

Arjun:

<syntaxhighlight lang="c">
#include<stdio.h>
int main()
{
int x=10, y;
y = (x++) + (++x);
printf("%d %d %d %d ", y, x++, x, ++x);
}
</syntaxhighlight>

'''a)''' 22,10,11,13

'''b)''' 22,11,11,11

'''c)''' 12,10,11,13

'''d)''' 22 13 13 13

None of the choices are correct as per [http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1124.pdf C standard]. This is because the statement
y = (x++) + (++x);

can causes undefined behavior, so does the statement
printf("%d %d %d %d ", y, x++, x, ++x);

C standard says that the side effects of an operation (for b = ++a; modification of a is a side-effect) need to be completed only before the next [https://en.wikipedia.org/wiki/Sequence_point sequence point]. This relaxation is given so that the compiler would be able to generate the most optimal code (which run faster). But as a consequence, programmer shouldn't do a read and a write from a memory location within a sequence point or otherwise the result would be undefined.

In the statement,
y = (x++) + (++x);

There are 2 reads to the memory location of x and 2 writes to the same within a sequence point. So, the result of this statement has no guarantee as per C standard.

Similarly, the statement
printf("%d %d %d %d ", y, x++, x, ++x);

is undefined. In a function call in C, the arguments are pushed onto the stack from right to left (the left most argument would be on top of the stack, so that variable no. of arguments can work in C). But the order in which the argument expressions are processed is not defined. The only thing defined is that all arguments must be processes before the next sequence point- which here is the execution of the called function.

I have seen many people saying C is so stupid because of these undefined behaviors. But that's the power of C. A programmer in C should know about these behaviors and avoid writing undefined codes.

<div class="fb-like" data-href="http://armi.in/wiki/NP,_NP_Complete,_NP_Hard" data-layout="standard" data-action="like" data-show-faces="false" data-share="true"></div>

<div class="fb-share-button" data-href="http://armi.in/wiki/NP,_NP_Complete,_NP_Hard" data-type="button_count"></div>

<disqus/>

[[Category:Code]]

Undefined Value

2013-11-30T00:54:23Z

Arjun:

<syntaxhighlight lang="c">
#include<stdio.h>
int main()
{
int x=10, y;
y = (x++) + (++x);
printf("%d %d %d %d ", y, x++, x, ++x);
}
</syntaxhighlight>

'''a)''' 22,10,11,13

'''b)''' 22,11,11,11

'''c)''' 12,10,11,13

'''d)''' 22 13 13 13

None of the choices are correct as per [http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1124.pdf C standard]. This is because the statement
y = x++ + ++x;

can causes undefined behavior, so does the statement
printf("%d %d %d %d ", y, x++, x, ++x);

C standard says that the side effects of an operation (for y = ++x; modification of x is a side-effect) need to be completed only before the next [https://en.wikipedia.org/wiki/Sequence_point sequence point]. This relaxation is given so that the compiler would be able to generate the most optimal code (which run faster). But as a consequence, programmer shouldn't do a read and a write from a memory location within a sequence point or otherwise the result would be undefined.

In the statement,
y = (x++) + (++x);

There are 2 reads to the memory location of x and 2 writes to the same within a sequence point. So, the result of this statement has no guarantee as per C standard.

Similarly, the statement
printf("%d %d %d %d ", y, x++, x, ++x);

is undefined. In a function call in C, the arguments are pushed onto the stack from right to left (the left most argument would be on top of the stack, so that variable no. of arguments can work in C). But the order in which the argument expressions are processed is not defined. The only thing defined is that all arguments must be processes before the next sequence point- which here is the execution of the called function.

I have seen many people saying C is so stupid because of these undefined behaviors. But that's the power of C. A programmer in C should know about these behaviors and avoid writing undefined codes.

<div class="fb-like" data-href="http://armi.in/wiki/NP,_NP_Complete,_NP_Hard" data-layout="standard" data-action="like" data-show-faces="false" data-share="true"></div>

<div class="fb-share-button" data-href="http://armi.in/wiki/NP,_NP_Complete,_NP_Hard" data-type="button_count"></div>

<disqus/>

[[Category:Code]]

Undefined Value

2013-11-30T00:50:51Z

Arjun:

<syntaxhighlight lang="c">
#include<stdio.h>
int main()
{
int x=10, y;
y = x++ + ++x;
printf("%d %d %d %d ", y, x++, x, ++x);
}
</syntaxhighlight>

'''a)''' 22,10,11,13

'''b)''' 22,11,11,11

'''c)''' 12,10,11,13

'''d)''' 22 13 13 13

None of the choices are correct as per [http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1124.pdf C standard]. This is because the statement
y = x++ + ++x;

can causes undefined behavior, so does the statement
printf("%d %d %d %d ", y, x++, x, ++x);

C standard says that the side effects of an operation should be complete only before the next [https://en.wikipedia.org/wiki/Sequence_point sequence point]. This relaxation is given so that the compiler would be able to generate the most optimal code (which run faster). But as a consequence, programmer shouldn't do a read and a write from a memory location within a sequence point or otherwise the result would be undefined.

In the statement,
y = x++ + ++x;

There are 2 reads to the memory location of x and 2 writes to the same within a sequence point. So, the result of this statement has no guarantee as per C standard.

Similarly, the statement
printf("%d %d %d %d ", y, x++, x, ++x);

is undefined. In a function call in C, the arguments are pushed onto the stack from right to left (the left most argument would be on top of the stack, so that variable no. of arguments can work in C). But the order in which the argument expressions are processed is not defined. The only thing defined is that all arguments must be processes before the next sequence point- which here is the execution of the called function.

I have seen many people saying C is so stupid because of these undefined behaviors. But that's the power of C. A programmer in C should know about these behaviors and avoid writing undefined codes.

<div class="fb-like" data-href="http://armi.in/wiki/NP,_NP_Complete,_NP_Hard" data-layout="standard" data-action="like" data-show-faces="false" data-share="true"></div>

<div class="fb-share-button" data-href="http://armi.in/wiki/NP,_NP_Complete,_NP_Hard" data-type="button_count"></div>

<disqus/>

[[Category:Code]]
[[Category:C]]

MediaWiki:Codepage

2013-11-30T00:47:25Z

Arjun: Created page with "Category:Code"

Category:Code

MediaWiki:Code

2013-11-30T00:46:52Z

Arjun:

Code

MediaWiki:Code

2013-11-30T00:45:54Z

Arjun:

Category:Code

MediaWiki:Code

2013-11-30T00:45:44Z

Arjun:

[Category:Code]

MediaWiki:Code

2013-11-30T00:45:35Z

Arjun: Created page with "Category:Code"

[[Category:Code]]

File:Logo.png

2013-11-23T13:45:59Z

Arjun: