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Hello š
As promised before, here I go with a tutorial on creating a singly linked list using simple c programming. I wanted to start tutorials on embedded C programming but just to have a touch and feel of C programs I go with few programming posts from now.
Basically you need the follow basic knowledge for creating a linked list.
1)What are structures? how are the accessed in C?
2)Pointers, a Very basics like what are pointers? how to use them to access structure members??
3)Dynamic memory allocation, what it is?? how is it done???
Anyways, before I start about the singly linked list tutorial,Lets go through the basic we need for understanding the concept of the linked list
Lets start with structure,
Structure is basically a collection of one or more variable. For example, college maintains details of student like Name, University No, Gender, your dept etc etc.
Here Name is a string or array of characters, University no is a integer etc Like wise if we want to a group with differ variable of different data types we define a structure.
Sample of the structure template
struct s_details
{
int USN;
char Gender;
};
The struct is the keyword to define a structure template. Once the structure template is defined the memory is not assigned, but the after structure variables the memory is assigned. Sample struct templates and the way the variables can be defined is shown below.
struct s_details
{
int USN;
char Gender;
}student1; Ā /*student1 is a variable that is defined just after the structure template before ;*/
OR
struct s_details
{
int USN;
char Gender;
};
main()
{
struct s_details student1; /*here its defined as a local variables like others*/
The student1 is a variable of type struct s_details and USN,Gender are the members of the struct s_details structure.
once the structure is defined we should be able to access the structure members, we can access The structure member in two ways
1)By using the structure variable.
2)By using pointer to the structure.
Lets have a look at the two type in a very quick way and look for creating a singly linked list.
1)By using structure variable.
Once the variable of type struct s_details is declared, here the variable is student1 we can use the operator “.” to access the member.
Example1 : I wanna assign the value 27 for the member USN.
student1.USN=27;Ā /*this assign’s the value 27 to the student1’s member USN.*/
Example2 : Now If i wanna assign ‘M’ to the member Gender.
student1.Gender='M';/*this assign’s M character to the student1’s member Gender.*/
2)By using Pointer to the structure.
Like the way we define a variable of type struct s_details , we define a pointer to the structure.
struct s_details
{
int USN;
char Gender;
}student1,*temp; Ā /* (*temp) is a pointer of type struct s_details*/
As a basic, after declaring a pointer we need to tell the pointer about the address it has to point, That is done by the following.
<code>main()
{
temp=&student1; //gives the address of the student1 to the pointer temp</code>
Now u can access the structure members using this operator “->“.
Example1 : As the example before, I wanna assign the value 47 for the member USN.
temp->USN=42; /* assigns the value 47 to the struct member USN */
Example2 : If I want to assign the F to the Gender member.
temp->Gender=’F’ /*assigns ‘F’ character to the Member Gender*/
Finally these basic can drive you and will help you to understand the Linked List Code and logic.
Now, Coming to the linked list Concept its just a way Where in the memory is being allocated on During Run time of the program. Instead of you Declaring a variable and theĀ compilerĀ reserving the Memory location during compiling time, The memory is allocated During run time of the program. This isĀ referredĀ as the “DYNAMIC MEMORY ALLOCATION”.
The following Diagrams should give you a brief Logic on creating a Linked list in C.
The structure that is considered for linked list has the following
So as you can see on your right, The whole structure is from now termed as NODE, a terminology usually used in the linked list process. So the structure template is as follow
Struct Node
{
int data; // this is the data
struct node *addr; /* this is the pointer that points to the next location*/
};
So the node is ready for programming it as the Linked list.
what is the basic logic.??
The figure blow helps you to understand it better.
The Node contains a Data which is for our reference to check whether the programming is working or not, The ADDR in the node points to the next node’s Address. Similarly the next node points to the other one.But the First node is taken as a Reference and is referred as Header.
Now the dynamic memory allocation is done my malloc function in the program. So just for your information malloc is a function that is being called for memory allocation during the run time. And the end of linked List always made null.
With this details I give a sample Code which creates a linked list of 10 nodes.
/********************************************************************************************************************************
The program creates a linked list of 10 nodes, The program is run on gcc compiler!!
*********************************************************************************************************************************/
#include<stdio.h>
#include<stdlib.h> //headerfile to use malloc() function.
struct node
{
int a;
struct node *p;
}hdr;
main()
{
struct node *present,*previous;
int i;
previous=&hdr;
for(i=0;i<10;i++)
{
// present pointer points at the memory allocated by malloc.
present=malloc(sizeof (struct node));
//new address is assigned to the header (at i=0).
previous->p=present;
// the value is given to the data.
present->a=i;
// control is passed.
previous=present;
printf("the adress created is %p\n",present);
printf("the value present in the allocated memory is %d\n",present->a);
if(i==9)
{
// indicates the end of linked list.
present->p=NULL;
}
}
}
Thanks for reading My post. Hope it helped atleast some of you guys. I believe in sharpening the blade before I get into the cutting process, so Have focused on basics more.
The UP-Coming Tutorials will be … Adding a Node to linked list… deleting a node… Circular linked list..
Then will be on the MSP430 Board and basic of the embedded OS and Services Operated by the Operating system. Thanks again and the blog will be updated Regularly from now.
Hello everyone…..:)
Its been almost 3 months, I have not written any posts. Was quite busy with my Personal work š
Ok, after Now What I am doing??? what I am working on???
Now I am undergoing an Embedded Training at Bangalore, Learning a lot… really a Lot..
Coming to what I am working on a Texas Instruments Microcontroller and I’m working n being trained on embedded programming.
The Programming on the embedded system is pretty interesting and very much to learn, I will be uploading tutorials on the embedded programming like process creation in linux, Interprocess communication(IPC) Using of software timer and developing device drivers etc etc…. all this will be on the new page of my blog.
The MSP430 is the microcontroller I am working on, Probably I ll be uploading the tutorials on the same soon.
Here are the Pics of what Texas Instuments Give you as a Microcontroller MSP430 Launch pad.
The Box contains.
I’ve misplaced the Quick Start Guide, so I give you guys the link for it.
You can order the MSP kit here
Worth buying.
My friend is very much ahead in MSP.You can follow the his blog . This blog is damn good one. Even I start learning it from there.
Anyways he is using IDE, I will be using Code Composer studio in my tutorials.
What are the features of the MSP430 can be seen on the datasheet so I won’t be giving all those details here. So please be stayed tuned on my site, You will be seeing interesting things and tutorials soon. Most of them are ready still a last few things to add up and post them.
This was During our 2nd year holidays, may be on month ofĀ JAN-FEB 2009 i guess.
After Exams I decided to organize a trek within our class. So started to search a nice place for trekking, With help of Google and Our Seniors, Myself and Arjun decided to trek MULLAYANAGIRI near chikmagalore.
Finally with great efforts, I managed to make sure 7 of our friends decided to go to trek.
Let me Introduce all these characters…
Myself, MANOJ this was my first trek.. had been for one day trek not of this kind.
ARJUN KUMAR Only person who was having experience Trekking, Level trekker.
NISCHAY, This is an interesting character… he is the person we considered to be a kind of entertainer.
HARISH, NO WORD.
GURU was harish’s friend.
PAVAN PATEL… full enthusiastic guy for all these kind of things.. he confirmed that he will be coming with us at last second.
Ullas.. This guy is a full bindas guy, wont even worry wat happens in next second.
We all decided to meet at Bangalore bus station at 9PM. Nischay has reached the bus station early… Then i reached… As per the timing display on the bus stand the last Bus was at 10PM. So we informed others to come early, Finally everyone come at around 10… then we came to know that the buses to chikmagalore are available anytime, even after 10.
Anyways non of us were in loss, Except Pavan who had come in his bike to bus stand and had parked it in bus stand parking place where he has to pay 100 bucks for 1 night.. Anyways non of us cared including pavan…
I still remember when all 6 of us were busy getting our bags on our shoulders, pavan was asking for discount with a poor teawala… “will take 7 tea,whats the discount u give me”. this is wat pavan asked the POOR guy at night 11PM.
Finally we were into bus at around 11.30… conductor gave us 7 seats next to each other.. we were chit chatting, and guru was still like unknown to all.. we tried to make his comfortable in our group.. all of us slept and We woke up inbetw , had tea there in mid way….
Again when we Woke up We were in chikmagalore bus station at sharp 5AM.
We freshed up ourselves there… All of us were eagarly for a hotel in exactly opposite to bus station… If i am write its SWATI hotel..
Had idli vada and since the bus to the Starting point of trekking was at 7:20 we went in search of kerosene which we found somewhere nearby… we needed it since WE HAD PLANNED TO HAVE CAMP FIRE AND COOK MAGGI (ONLY MAGGI).
We reached the starting point of the trek, its called SARPADARI š
looking at the mullayanagiri from the below… for ppl like us its like ” is it possible to trek this ” ???!!!
The one on right is the starting place for trek… The guys in the pic are pavan, harish and nischay(from left).
Yes we started… after just some 15min we realized that non of us had bought cameras.. we managed to take pic’s using our mobile phones.. only ullas and guru had mobile phone with proper cameras.. IT was freaking cold i had experienced…
After almost some 2-3hours of trek, We reached almost top… we reached a place where there were some 2caves.. and the water in the caves ware freezing.. from the start point pavan and ullas were the ppl who used to lag behind all of us… we used to wait till the come, better to say we used to take rest till then reach the point where we were, and then again start to trek… PAVAN used to shout at us saying “u ppl never give time for me to take rest”… even ullas used to shout.. but no one listened to them..
finally We reached the top!!! TOP OF THE MULLAYANAGIRI š š
After we Reached, the family that stays at the top would make food for us if we are small in no.. so since we were 7, we asked them. WE reached by 11:30 or 12… All of us were really hungry.. The person over there asked us to wait till 2 for lunch… so we all were busy enjoy the beauty of nature.. and taking snaps… There was a shooting going on over there..kannada movie.. SUPERMAN. not yet release.
After lunch we trekked towards baba budengiri š
At baba budengiri.. we had coffee… i think some egg food…
From baba budengiri we started walking towards GAALIKERI… this was the place where we had planned to camp over there…
From the second we started to trek down the mullayanagiri hills… pavan told us that he is gonna cook chicken for all of us… he actually was the one who put up the idea of spicy chicken in a drizzling rain and freezing cold…
Gaalikere is 5km from Baba budengiri…
We started to walk to Gaalikere.. it was already raining… anyways all of us walked in rain and reached Gaalikere…
After we Reached Gaalikere..Harish and guru decided to come back to bababudengiri for stay… where as rest of use decided to put up then tent for stay..
It was awesome experience over there… It was best… It was ultimate over gaalikere…
We put up a ten… all 5 of us stay in and wanted to fill our stomatch with something… anyways pavans chickens idea was impossible to be implemented
since neither we had hen… or even if we had hen it was poring heavily there.. We had our tent such a place, like around some 5-7km radius there was no human being around..
As usual, All of us were afraid… all of us hear all kinds of sound that could possibly make us feel afraid… i heard it as someone walking, ullas heard it as something else.. likewish with others too…
we had chapatti and jam as our dinner.. spoke up as much as possible… and at the end we wanted to sleep…
No one was ready to sleep at the corners, so myself and arjun slept at the edges of the tent…..
EXCEPT ULLAS and ARJUN, Myself.. nischay nor pavan had proper sleep…
Early morning around 6, there was no fog over there… so we decided to cook maggi (the chicken was like a dream over there)… pavan was the cook.. by the time we collected wood over the place and start to cook maggi, it was completely fog filled place….
the Fog over gaalikere was so much dense we couldnt see the person whom was standing 1meter away from us clearly.. In such a dense fog we ppl tried to put up fire.. we wasted as much as kerosene possible…
We realized that we cant and started to walk back to bababudengiri…
On the way we say dry wood and a stream of water… finally PAVAN made maggi for all of us.. as usual, since we helped him he could make it… š
The maggi i had in mid way of gaalikere and baba budengiri on the roadside was the best maggi ever i had in my life… it was the best on… THANKS PAVAN for that š š We came back to Banglore next day morning via chikmagalore… NISCHAY stayed back in chikmagalore at his Ganny’s place.
HERE are the fews of the photos of gaalikere and maggi š š
oohh hhoo…OOOps.. sorry… forgot… PAVAN has planned for an estate in chikmagalore….:) š
and nichay was the bloody who troubled throughtout tht trek… š š
MEMORIES, It was awesome š
Most of us may be knowing about the allotropes of carbon Like Diamond, Graphite, Fullerenes etc.
A new addition to the family of allotropes of carbon is GRAPHENE, Because of it special characteristics it is expected to Replace “SILICON” in the world on “ELECTRONICS”
Graphene is defined as a one atom thin sheet of carbon atoms arranged in a Hexagonal format OR a flat monolayer of carbon atoms that are tightly packed into a 2D honeycomb lattice.
Now, We are in a silicon era, since it well-know that the VLSI, ULSI technologies are the most recent technologies being used in the CHIP manufacture process and Using silicon the MOORE law prediction is being deviated.
Most of the research scholars and scientists Predict that the using graphene the deviation can be brought back to it actual prediction.
why is graphene given such importance in recent days???
What makes graphene a better material compared to others???
The above are the couple of questions that may keep going on usually in everyone mind.. so the below goes the answer.
Graphene, since it is a flat monolayer carbon atoms arranged in a hexagonal shape, it is easy in converting or manipulating the shape of the graphene into fullerene, or Carbon nanotubes or graphite.
In the below diagram we can see the convertion of graphene into fullerene, carbon nanotube and graphite.
Till recent past the hardest material found on earth was DIAMOND, but Now GRAPHENE replaces the place of Diamond. Considering the density of the graphene, i.e the density of the hexgonal shaped carbon atoms, The density of carbon atoms is so high that even when a HELIUM gas(helium has only on electron in its shell, so its the smallest element) is passed through the graphene monolayer , the helium gas couldn’t cross the graphene.
Coming to its electrical property, the mobility of electrons in graphene high when compared to any other metal and it has highly modifiable electrical property , it can be modified to play the role of conductor or insulator or semiconductor easily.
APPLICATIONS OF GRAPHENE
Just Be the words ” GRAPHENE- A MATERIAL THATS GOING TO REPLACE SILICON IN NEAR FUTURE” everyone can make out the range of applications that
graphene has in its hand.
Graphene is a promising material for electronics switching system, In field of Biotechnology and specially in touch screen technology.
Recently graphene is being used in field of biotechnology, using the graphene new nano pore device, these are the devices used in detection of single molecules. These can be used for the know the patters present in the DNA samples.
Graphene NanoRibbons(GNR) are alternatives to copper in integrated circuits. Since copper is the basic material used in the silicon chips, instead of copper for connections in the IC’s, GNR’s may be used.
Most of us might have seen the transparent monitors in movies like avatar, ironman, eagle eye etc… the one in blue color..
yes, those are the once that can be manufactured from graphene. The major advantage of those transparent monitor over the traditional onces is
that, there is no need of the back light which is a must in the traditional monitors.
The displays being manufactured may not be like the traditional one, i.e it may not be rigid kind of material. Since the grahene is a monolayer material and it has high felixiblity with having a great strength(tenstile strength is 200 times better than steel), These monitors of graphene can be flexiblity bent without any risk.
Now, Recently in 2008 IBM T J watson research center designed the fastest field-effect transistor (FET), operating at 26 GHz.
The noble prize in 2010 in physics was been awarded to Andre Geim and Konstantin Novoselov, both of the University of Manchester, “for groundbreaking experiments regarding the two-dimensional material graphene.”
Here is the video that can make u ppl how will the future of graphene will be …..
As the name suggests, yes this is a invention by 2 INDIAN innovators Pragnesh Dudhaiya and Aalok Bhatt from Nirma University in Ahmedabad, INDIA.
This was being revealed to the world on may 2010, Basically the helmet uses the solar energy and wind energy to change the Cellphones. As per the experiment done by the innovators, this charger can charge the cellphone in about 40min.The helmet charger uses solar energy during morning times, whereas it harnesses the wind energy for charging the cellphones. According to the pragnesh and aalok this helmet costs Rs.1000.
Its a great work by them to come up with a innovative idea and implement them, lets us congratulate for their work.
But the only question remains is would there by any side effects on the health of the person using this helmet???
Hello,
Happy new year to all of you.Its been long time I have not posted any of the Articles.
I have noticed that some person is following my blog and specially the post “Finally the details of the Obstacle Avoiding robot” regularly, since he/she is following that article, its sure that the he/she is a beginner in the robotics field like me and is trying to make the obstacle avoiding robot. Thought will help that person with some additional information. Here is the PDF file which has helped me to learn lot of thing of the robots so hope you People like it, specially the person whom I mentioned earlier. I had downloaded this pdf from some blog, Since I have lost the link of the blog I am uploading the file directly.
Click Here to download.
Thanks for visiting my blog, thanks for the support.
This is something crazy i have tried.
I wanted to completely disassemble My CORBY phone, But i couldnt do it completely.
Actually i didn’t dare to disassemble it after a stage where i knew if i go further, the phone wouldn’t work anymore.
Here are the Pics,
But at the end i was much interested with this photo. The camera of the corby, I Don’t know why it attracted my attention. Now i am interested to interface of cameras with DSP processor… š š š
Hi,
This was a nice article from EFY, I loved the article. And many of my friends like it.
Thought of sharing it here…
I know the quality of the image is not good, trust me.. the article is SUPERB for those who like embedded systems.
I suggest you to SAVE both the photos to your computer And then read it so that something not properly visible can be zoomed in.
Hello,
Here is the list of Top 100 Electronics and IT companies in India.
The above ranking is based on the basis of REVENUE.
The post is based on the article published by Electronics For You(EFY) Ā October 2010 Vol. 42 No 10
Manoj Kumar S 