Seriously struggling with C

[RG]

Greetings friends,

This semester I have started a course in C programming. I was moving
along fine until I reached to the topic of loops (feeling embarrassed
among you elite programmers). My prof. would post program questions
and the solutions online. For practice I would try to do the problems.
I would reach to a certain point in the code, for example as far as
error trapping, but when the loop arrives, like knowing whether to use
for, while do, how to properly use the increment and decrements, and
counters,I am just not proficient in it and the class is moving ahead.
Eventually i would have to look at the solution and wondering to
myself, the reason i could not think of it. What ticks me off is that
other kids are getting this stuff easily, while I am having a hard
time.Kindly advise me on what actions I shoul take. I would
particularly like to have an idea of the thought process to engage in
when given the programme to write.
Thanks for your time and consideration.

RG

[priyam.trivedi]

Hi!
I am not an expert in programming but I do like programming as it is
"mentally stimulating." The first thing that I will tell you is don't
compare yourselves with others, once you start doing that, you are
going to feel worse.
Try seeing programming like a game. First, try and build your own
solution from a mathematical perspective, without taking the
constraints of C programming. I wont say that it will be easy, but give
it a shot. Try to write an alogorithm, I dont use them much, but it
does help to understand the direction in which the program flows. So
once you have your solution try writing it in your own words. And then
in the end use the syntax of the programming language and try it out in
your editor.
I dont how much this will help you. I am a freshman myself, and I am
just telling you the way I see it. Just take it as a challenge and I am
sure you will be fine.
Take care and Good Luck.
Priyam

[Nick Keighley]

RG wrote:

This semester I have started a course in C programming. I was moving
along fine until I reached to the topic of loops (feeling embarrassed
among you elite programmers). My prof. would post program questions
and the solutions online. For practice I would try to do the problems.
I would reach to a certain point in the code, for example as far as
error trapping, but when the loop arrives, like knowing whether to use
for, while do, how to properly use the increment and decrements, and
counters,
one cause of your problems may be that there is no definitive right or
wrong answer. Anything you can do with a while() you can do with a
for(),
and the functionality of a for() can be duplicated with a while() and a

couple of other statements. C's for() is very powerful (some might
argue,
too powerful). I tend to classify loops into two main types.

- a fixed known number of iterations (times around the loop), for these
I
use for()
- an iterate until some condition is met

// loop n times
for (i = 0; i < n; i++)
do_something ();

I'd just learn this as a piece of boilerplate code to drop in when you
need a
known number of iterations.

// loop while some condition holds
while (condition)
do_something();

You can pretty much do anything with those two.
There is also a while at the end:-

do {
do_something()
}
while (condition);

but it practice this is far less useful. note it always does at least
one iteration.

A C idiom for a loop that goes "forever"

for (;;) // never stops
{
do_something();
if (exit_condition )
break;
do_something_el se();
}

this can sometimes be useful, I'd avoid it until you are comfortable
with the first two forms.

Where C can be confusing is when the "cleverness " of the for() is
exploited.

// walk a linked list
for (i = head; i != NULL; i = i->next)
flop_node (i->data);

If this confuses you, use a while()

for (i = 1, j = 1; i < k, j < l; i++, j + 2)
something_scary (i, j);

if this confuses you... chop the program listing into little pieces and
feed it
to the author of the code :-)

Keep It Simple is the first lore of programming
I am just not proficient in it and the class is moving ahead.
Eventually i would have to look at the solution and wondering to
myself, the reason i could not think of it. What ticks me off is that
other kids are getting this stuff easily, while I am having a hard
time.Kindly advise me on what actions I shoul take. I would
particularly like to have an idea of the thought process to engage in
when given the programme to write.

--
Nick Keighley

The fscanf equivalent of fgets is so simple
that it can be used inline whenever needed:-
char s[NN + 1] = "", c;
int rc = fscanf(fp, "%NN[^\n]%1[\n]", s, &c);
if (rc == 1) fscanf("%*[^\n]%*c);
if (rc == 0) getc(fp);

[August Karlstrom]

RG wrote:

Greetings friends,

This semester I have started a course in C programming. I was moving
along fine until I reached to the topic of loops (feeling embarrassed
among you elite programmers). My prof. would post program questions
and the solutions online. For practice I would try to do the problems.
I would reach to a certain point in the code, for example as far as
error trapping, but when the loop arrives, like knowing whether to use
for, while do, how to properly use the increment and decrements, and
counters,I am just not proficient in it and the class is moving ahead.
Eventually i would have to look at the solution and wondering to
myself, the reason i could not think of it. What ticks me off is that
other kids are getting this stuff easily, while I am having a hard
time.Kindly advise me on what actions I shoul take. I would
particularly like to have an idea of the thought process to engage in
when given the programme to write.
Thanks for your time and consideration.

Please, provide an example of something you don't grasp. The while loop
is probably the easiest loop construct to understand.

Example:

/* Show the contents of the array a of length len. */
k = 0;
while (k < len) {
printf("%d\n", a[k]);
k++;
}
/* Just by looking at the loop guard, we know that k >= len here
(actually k == len). */
August

--
I am the "ILOVEGNU" signature virus. Just copy me to your
signature. This email was infected under the terms of the GNU
General Public License.

[Rod Pemberton]

"RG" <su************ @hotmail.com> wrote in message
news:11******** *************@z 14g2000cwz.goog legroups.com...

Greetings friends,

This semester I have started a course in C programming. I was moving
along fine until I reached to the topic of loops <snip> like knowing whether to use
for, while do, how to properly use the increment and decrements, and
counters, <snip> I would
particularly like to have an idea of the thought process to engage in
when given the programme to write.

This is my thought process on loops:
1) while - never use
2) for - use as much as possible
3) do while - only use when necessary

I'll explain. The while loop only checks for a single statement being true.
It is very simple. So simple in fact that it really is useless. It
duplicates functionality that exists in a for loop. Therefore, why use it?
Many C programmers don't. while(1) becomes for(;;). while (a<b) becomes
for(;a<b;) .The for loop is a very powerful loop construct that can
implement almost any loop. The only time you don't want to use a for loop
is when the block of code in the loop needs to execute at least once. When
the code 'needs to execute at least once,' you use the do while loop. The
last flow control constructs are procedures, functions, and switches.
Procedures and functions aren't usually used for looping. The switch
statement is useful any time the data or a counter you've created doesn't or
won't increment or decrement by one.

The next step is to 'see' how a for loop works when it is written as a while
loop:

i=0;
while(i<10)
{
/* continue starts here for while() */
/* ...code body... */
/* continue starts here for for() */
i++;
}

That is the same as this for loop:

for (i=0; i<10; i++)
{
/* ...code body... */
}

The continue statement in a while continues execution at the top of the
while. But, for the for loop, execution continues before the third
expression (i++).
Rod Pemberton

[billh40]

RG wrote:

Greetings friends,

This semester I have started a course in C programming. I was moving
along fine until I reached to the topic of loops (feeling embarrassed
among you elite programmers). My prof. would post program questions
and the solutions online. For practice I would try to do the problems.
I would reach to a certain point in the code, for example as far as
error trapping, but when the loop arrives, like knowing whether to use
for, while do, how to properly use the increment and decrements, and
counters,I am just not proficient in it and the class is moving ahead.
Eventually i would have to look at the solution and wondering to
myself, the reason i could not think of it. What ticks me off is that
other kids are getting this stuff easily, while I am having a hard
time.Kindly advise me on what actions I shoul take. I would
particularly like to have an idea of the thought process to engage in
when given the programme to write.
Thanks for your time and consideration.

RG

Go to www.bloodshed.net and download their free C/C++ compiler.
Then use it to test out your code to learn how to program in C/C++.

Bill Hanna

[Keith Thompson]

"Rod Pemberton" <do*********@so rry.bitbucket.c mm> writes:

"RG" <su************ @hotmail.com> wrote in message
news:11******** *************@z 14g2000cwz.goog legroups.com...

Greetings friends,

This semester I have started a course in C programming. I was moving
along fine until I reached to the topic of loops <snip>

like knowing whether to use
for, while do, how to properly use the increment and decrements, and
counters,

<snip>

I would
particularly like to have an idea of the thought process to engage in
when given the programme to write.

This is my thought process on loops:
1) while - never use
2) for - use as much as possible
3) do while - only use when necessary

I'll explain. The while loop only checks for a single statement being true.

Condition, not statement.
It is very simple. So simple in fact that it really is useless. It
duplicates functionality that exists in a for loop. Therefore, why use it?

That's bad advice. Use while() whenever it's the most natural
construct to use. Arbitrarily transforming "while (condition)" into
"for (;condition;)" is foolish.

--
Keith Thompson (The_Other_Keit h) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.

[Keith Thompson]

bi*****@aol.com writes:

RG wrote:

Greetings friends,

This semester I have started a course in C programming. I was moving
along fine until I reached to the topic of loops (feeling embarrassed
among you elite programmers). My prof. would post program questions
and the solutions online. For practice I would try to do the problems.
I would reach to a certain point in the code, for example as far as
error trapping, but when the loop arrives, like knowing whether to use
for, while do, how to properly use the increment and decrements, and
counters,I am just not proficient in it and the class is moving ahead.
Eventually i would have to look at the solution and wondering to
myself, the reason i could not think of it. What ticks me off is that
other kids are getting this stuff easily, while I am having a hard
time.Kindly advise me on what actions I shoul take. I would
particularly like to have an idea of the thought process to engage in
when given the programme to write.
Thanks for your time and consideration.

Go to www.bloodshed.net and download their free C/C++ compiler.
Then use it to test out your code to learn how to program in C/C++.

How is that useful? Since the OP is taking a course in C programming,
it's safe to assume he already has access to a C compiler. If there's
something about the bloodshed compiler that makes it particularly
useful for beginners, you might want to say so.

BTW, what do you mean by "C/C++ compiler"? There is no "C/C++" language.

--
Keith Thompson (The_Other_Keit h) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.

[Rod Pemberton]

"Keith Thompson" <ks***@mib.or g> wrote in message
news:ln******** ****@nuthaus.mi b.org...

"Rod Pemberton" <do*********@so rry.bitbucket.c mm> writes:

"RG" <su************ @hotmail.com> wrote in message
news:11******** *************@z 14g2000cwz.goog legroups.com...

Greetings friends,

This semester I have started a course in C programming. I was moving
along fine until I reached to the topic of loops <snip>

like knowing whether to use
for, while do, how to properly use the increment and decrements, and
counters,

<snip>

I would
particularly like to have an idea of the thought process to engage in
when given the programme to write.

This is my thought process on loops:
1) while - never use
2) for - use as much as possible
3) do while - only use when necessary

I'll explain. The while loop only checks for a single statement being true.
Condition, not statement.
Expression, not condition? I doubt the OP is familiar with any language or
definitions of ISO/ANSI specifications, so please don't criticize me for
phrasing to his level of understanding.
It is very simple. So simple in fact that it really is useless. It
duplicates functionality that exists in a for loop. Therefore, why use

it?
That's bad advice. Use while() whenever it's the most natural
construct to use. Arbitrarily transforming "while (condition)" into
"for (;condition;)" is foolish.

Not using the braces of a compound-statement for while's and if-else's when
there is a single statement is also the most natural construct to use. But,
of course, as we've seen many times here, that leads to later problems.
People forget to add the braces when a statement is converted to a
compound-statement. The same holds true for the while statement. A while
will frequently be converted to a for sometime in the future. At which
point, the programmer is likely to introduce an error. Why not just do it
manner which reduces the chance that an error, now or in the future, is
introduced? I've seen you suggest this on many occasions. I find it odd
that you'd take a contrary position now.

Rod Pemberton

[August Karlstrom]

Keith Thompson wrote:

"Rod Pemberton" <do*********@so rry.bitbucket.c mm> writes:

[about the while-statement]

It is very simple. So simple in fact that it really is useless. It
duplicates functionality that exists in a for loop. Therefore, why use it?

That's bad advice. Use while() whenever it's the most natural
construct to use. Arbitrarily transforming "while (condition)" into
"for (;condition;)" is foolish.

I agree. Moreover, the advantage of the "while" statement over the C
"for" statement is its clear semantics. But hey, how many C programmers
care about that ;-).
August

--
"C is what happened when Algol and Fortran got drunk and spent the
weekend together." -- Scott More (from the thread "Java or C++" in
comp.programmin g 2005.10.19)