Beginners Tutorial : The C-language :: Discussions

Hello everyone, I am simplycoder and welcome to C-programing discussions.
In this thread, you can post your questions and I shall try to answer them to best of my knowledge.
I prefer the questions which are parallel to the thread dedicated to tutorials,but I shall answer any question which I think I can.
So just shoot the questions, some one would answer your questions sooner or later as this forum has a lot of good programers.

@simplycoder: Give us some debugging questions too.

Can you explain this code ... . . .. !

Code:

 #include<stdio.h>
void main()
 {
 int i=1,a;
 a = ++i + (++i)++ + ++i ;
 printf("%d",a);
 }

How the middle 'i' is being calculated..

@TheV:

I dont think you compiler is going to like this, I have not written the code as yet, but then I do think that post increment is going to make some troubles with this program.

As a thumb rule, modifying any statement more than once without a sequence point will lead to undefined results in C.
in your case you have modified i multiple times without a sequence point, this will cause sequence point ambiguity.

The best thing is, you can write your code in some other language except for C++ say in a Java, find out your result and let us know if they are same or not.

@simplycoder... I have compiled this code in Turbo C++ and it's giving me 14 as output...but I can't make it out the actual calculating procedure..

TheV: Is it running without any error?

@TheV: Now rewrite yout code in Java if you can and post the answer.
See the sequence point ambiguity for the same.

Friends have you compiled the code ,,,,,, I have compiled in both Turbo C++ and borland C++ . I am getting the same
answer as 14 . .. Are you people got the same answer or having any error...??

@simplycoder: I have compiled the same code after writing in java ... and I am getting 4 error.. But I am not concern about java compiler
As java and C compilers are different so the result is different but I have written this code in C and I am getting answer as
14. Are you compiled this code in C ? Are you getting any error ?

I am getting the post-increment errors as I pointed out.

I dont really get you on this note. AFAIK, this is sequence point error.

You can try the expression : a = ++i + ++i + ++i; in java and c. This wont give you any error, but surely will give you different answers.

But I am not getting any error.....

That what I wanted to say you in my above lines....

In java It is giving me ---- 9
but in C ------------------12

In C I understood the concept..It first increases the pre-increment of ' i ' and then placed to evaluate the expression..(Correct me if wrong)

Can you explain me what is concept in java...? How 9 output is been shown in java....

@TheV: surprisingly, for me in on my devC++, its 10 from C program.
this is the sequence point ambiguity.
java works in the same way in case of increment.
but then for C its just sequence point ambiguity. check for google on the same for sequence point ambiguity.

i got the output as 10.How come will the output will differ in Turboc3 and Devc?

Hi simply coder ......
your Tutorials are really Helpful.. and thanking you for your Efforts....

have a question regarding the sample program given in 16 th tutorial(Menu Driven program)...
>> in your program the

is placed out side the Switch , its ok when when the case 1 to 4 occurs
but when the Default case is executed , it also prints the answer !
i think it will be better if the printf is placed inside each cases ,(but then we have to type it 4 times )
any other suggestion??

@H.Ali: Yeah, you are correct. My Bad.
I think we have to place printf you are correct. We should print it 4 times. That is very easy and nothing new is to be learnt.
thanks for pointing it out.

please explain the logic to print pascals triangle [using *]

To program any pattern, just make a table like this.
[TABLE="class: grid"]
[TR]
[TD]Row.no[/TD]
[TD]Stars[/TD]
[TD]Blanks[/TD]
[/TR]
[TR]
[TD]1[/TD]
[TD]1[/TD]
[TD]4[/TD]
[/TR]
[TR]
[TD]2[/TD]
[TD]2[/TD]
[TD]3[/TD]
[/TR]
[TR]
[TD]3[/TD]
[TD]3[/TD]
[TD]2[/TD]
[/TR]
[TR]
[TD]4[/TD]
[TD]4[/TD]
[TD]1[/TD]
[/TR]
[TR]
[TD]5[/TD]
[TD]5[/TD]
[TD]0[/TD]
[/TR]
[TR]
[TD]n[/TD]
[TD]n[/TD]
[TD]n-stars[/TD]
[/TR]
[/TABLE]


By using this logic, you can print the stars.
Make sure you print blanks first and then stars.

Code is not getting compiled in java.... giving error at (++i)++

hi simply coder......i am from production engg. and i will have to face and campus drive in coming month. Tcs is coming for campus..they want us to have a fundamental knowledge of a language...can u help me to learn the basic of c.

You can refer the tutorial which I wrote on this forum,
Pointers is an important topic left uncovered in tutorial.
Hopefully soon I shall get some time to start writing from where I left.

For book I suggest http://en.wikipedia.org/wiki/The_C_Programming_Language nice book, and a must read for insights of the language.

If you have some doubt or stuck in analysis, post it down here.