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Groups > comp.lang.c > #4924 > unrolled thread
| Started by | "Bill Cunningham" <nospam@nspam.invalid> |
|---|---|
| First post | 2011-05-28 15:28 -0400 |
| Last post | 2011-06-01 09:02 +0200 |
| Articles | 20 on this page of 49 — 17 participants |
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error in code "Bill Cunningham" <nospam@nspam.invalid> - 2011-05-28 15:28 -0400
Re: error in code pozz <pozzugno@gmail.com> - 2011-05-28 21:49 +0200
Re: error in code "Bill Cunningham" <nospam@nspam.invalid> - 2011-05-28 16:12 -0400
Re: error in code Shao Miller <sha0.miller@gmail.com> - 2011-05-28 15:33 -0500
Re: error in code "Bill Cunningham" <nospam@nspam.invalid> - 2011-05-28 17:12 -0400
Re: error in code Geoff <geoff@invalid.invalid> - 2011-05-28 14:26 -0700
Re: error in code Shao Miller <sha0.miller@gmail.com> - 2011-05-28 16:29 -0500
Re: error in code Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2011-05-28 17:26 -0600
Re: error in code Geoff <geoff@invalid.invalid> - 2011-05-28 14:20 -0700
Re: error in code "Bill Cunningham" <nospam@nspam.invalid> - 2011-05-29 02:16 -0400
Re: error in code Lew Pitcher <lpitcher@teksavvy.com> - 2011-05-28 16:35 -0400
Re: error in code "Bill Cunningham" <nospam@nspam.invalid> - 2011-05-29 15:50 -0400
Re: error in code Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2011-05-29 20:39 -0600
Re: error in code Geoff <geoff@invalid.invalid> - 2011-05-28 13:46 -0700
Re: error in code Nobody <nobody@nowhere.com> - 2011-05-28 23:06 +0100
Re: error in code Ian Collins <ian-news@hotmail.com> - 2011-05-29 10:10 +1200
Re: error in code Ian Collins <ian-news@hotmail.com> - 2011-05-29 10:09 +1200
Re: error in code Angel <angel+news@spamcop.net> - 2011-05-28 22:28 +0000
Re: error in code Ian Collins <ian-news@hotmail.com> - 2011-05-29 10:37 +1200
Re: error in code Angel <angel+news@spamcop.net> - 2011-05-28 22:45 +0000
Re: error in code Ian Collins <ian-news@hotmail.com> - 2011-05-29 10:48 +1200
Re: error in code Angel <angel+news@spamcop.net> - 2011-05-28 22:56 +0000
Re: error in code Seebs <usenet-nospam@seebs.net> - 2011-05-29 00:38 +0000
Re: error in code "Morris Keesan" <mkeesan@post.harvard.edu> - 2011-05-28 23:11 -0400
Re: error in code Keith Thompson <kst-u@mib.org> - 2011-05-28 15:54 -0700
Re: error in code Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2011-05-28 17:23 -0600
Re: error in code jacob navia <jacob@spamsink.net> - 2011-05-29 19:30 +0200
Re: error in code Geoff <geoff@invalid.invalid> - 2011-05-29 18:14 -0700
Re: error in code Keith Thompson <kst-u@mib.org> - 2011-05-29 18:50 -0700
Re: error in code Geoff <geoff@invalid.invalid> - 2011-05-29 19:10 -0700
Re: error in code Seebs <usenet-nospam@seebs.net> - 2011-05-30 02:54 +0000
Re: error in code Geoff <geoff@invalid.invalid> - 2011-05-29 20:35 -0700
Re: error in code Seebs <usenet-nospam@seebs.net> - 2011-05-30 06:15 +0000
Re: error in code jacob navia <jacob@spamsink.net> - 2011-05-30 08:46 +0200
Re: error in code Geoff <geoff@invalid.invalid> - 2011-05-30 18:50 -0700
Re: error in code Keith Thompson <kst-u@mib.org> - 2011-05-31 10:49 -0700
Re: error in code Peter Nilsson <airia@acay.com.au> - 2011-05-29 21:04 -0700
Re: error in code jacob navia <jacob@spamsink.net> - 2011-05-30 08:44 +0200
Re: error in code Tim Rentsch <txr@alumni.caltech.edu> - 2011-05-31 01:35 -0700
Re: error in code pacman@kosh.dhis.org (Alan Curry) - 2011-05-31 23:36 +0000
Re: error in code Tim Rentsch <txr@alumni.caltech.edu> - 2011-06-01 03:01 -0700
Re: error in code Keith Thompson <kst-u@mib.org> - 2011-06-01 08:08 -0700
Re: error in code Tim Rentsch <txr@alumni.caltech.edu> - 2011-06-01 12:50 -0700
Re: error in code Keith Thompson <kst-u@mib.org> - 2011-06-01 13:26 -0700
Re: error in code Tim Rentsch <txr@alumni.caltech.edu> - 2011-06-02 18:10 -0700
Re: error in code jacob navia <jacob@spamsink.net> - 2011-06-03 11:55 +0200
Re: error in code Tim Rentsch <txr@alumni.caltech.edu> - 2011-06-03 19:37 -0700
Re: error in code jacob navia <jacob@spamsink.net> - 2011-06-04 08:13 +0200
Re: error in code Nisse Engström <news.NOSPAM.idf0Z@luden.se> - 2011-06-01 09:02 +0200
Page 1 of 3 [1] 2 3 Next page →
| From | "Bill Cunningham" <nospam@nspam.invalid> |
|---|---|
| Date | 2011-05-28 15:28 -0400 |
| Subject | error in code |
| Message-ID | <4de14d0c$0$1943$bbae4d71@news.suddenlink.net> |
I am trying here to calculate a mean of 3 values. I do not understand
the errors the compiler returned I've never seen them.
#include <stdio.h>
void mean(double *avg, int periods)
{
double val;
val = *avg / periods;
printf("%.2f\n", val);
}
int main(void)
{
double a[] = 2.2, 4.2, 5.00;
mean(a, 3);
}
p.c: In function `main':
p.c:12: invalid initializer
p.c:12: parse error before numeric constant
What's it trying to tell me?
Bill
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| From | pozz <pozzugno@gmail.com> |
|---|---|
| Date | 2011-05-28 21:49 +0200 |
| Message-ID | <irrjl0$iuv$1@nnrp.ngi.it> |
| In reply to | #4924 |
Il 28/05/2011 21:28, Bill Cunningham ha scritto:
> void mean(double *avg, int periods)
> {
> double val;
> val = *avg / periods;
> printf("%.2f\n", val);
> }
avg is a pointer to double. *avg is a double. If you write
*avg / periods
your dividing one double value by periods.
In your case, avg points to an array of double values. The number of
elements in the array is periods. So you have to write a cycle to sum
all the periods elements together. At last, you can divide by periods.
> int main(void)
> {
> double a[] = 2.2, 4.2, 5.00;
^
You are initializing an array. In C you can do that with curly backets {}:
double a[] = { 2.2, 4.2, 5.00 };
> mean(a, 3);
^
In this case you are passing the number of elements of a[] array. I
suggest to use a syntax like the following:
mean(a, sizeof(a) / sizeof(a[0]));
or define a generic macro if you're going to use this syntax in several
points:
#define SIZEARRAY(a) (sizeof(a) / sizeof(a[0]))
In this way, you can modify the number of elements in the
initialization, but you haven't to modify the number of elements that
will be automatically calculated by the preprocessor.
Of course, this is valid only for static allocated array. You you
dinamically allocate an array, you are responsible to take its lenght in
some variable.
> }
> p.c: In function `main':
> p.c:12: invalid initializer
> p.c:12: parse error before numeric constant
>
> What's it trying to tell me?
See above.
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| From | "Bill Cunningham" <nospam@nspam.invalid> |
|---|---|
| Date | 2011-05-28 16:12 -0400 |
| Message-ID | <4de15747$0$1954$bbae4d71@news.suddenlink.net> |
| In reply to | #4929 |
pozz wrote:
> Il 28/05/2011 21:28, Bill Cunningham ha scritto:
>> void mean(double *avg, int periods)
>> {
>> double val;
>> val = *avg / periods;
>> printf("%.2f\n", val);
>> }
>
> avg is a pointer to double. *avg is a double. If you write
>
> *avg / periods
>
> your dividing one double value by periods.
>
> In your case, avg points to an array of double values. The number of
> elements in the array is periods. So you have to write a cycle to sum
> all the periods elements together. At last, you can divide by periods.
That's what I don't know how to do. Write a cycle. It's these little caveats
in C that confuse me most. Functions I am grasping. Writing cycles not so
much.
>> int main(void)
>> {
>> double a[] = 2.2, 4.2, 5.00;
> ^
>
> You are initializing an array. In C you can do that with curly
> backets {}:
> double a[] = { 2.2, 4.2, 5.00 };
>
>> mean(a, 3);
> ^
>
> In this case you are passing the number of elements of a[] array. I
> suggest to use a syntax like the following:
>
> mean(a, sizeof(a) / sizeof(a[0]));
What's the sizeof(a[0]) mean?
> or define a generic macro if you're going to use this syntax in
> several points:
>
> #define SIZEARRAY(a) (sizeof(a) / sizeof(a[0]))
>
> In this way, you can modify the number of elements in the
> initialization, but you haven't to modify the number of elements that
> will be automatically calculated by the preprocessor.
>
> Of course, this is valid only for static allocated array. You you
> dinamically allocate an array, you are responsible to take its lenght
> in some variable.
>
>> }
>> p.c: In function `main':
>> p.c:12: invalid initializer
>> p.c:12: parse error before numeric constant
>>
>> What's it trying to tell me?
>
> See above.
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| From | Shao Miller <sha0.miller@gmail.com> |
|---|---|
| Date | 2011-05-28 15:33 -0500 |
| Message-ID | <irrm6t$17v$1@dont-email.me> |
| In reply to | #4933 |
On 5/28/2011 3:12 PM, Bill Cunningham wrote:
> pozz wrote:
>> Il 28/05/2011 21:28, Bill Cunningham ha scritto:
>>> void mean(double *avg, int periods)
>>> {
>>> double val;
>>> val = *avg / periods;
>>> printf("%.2f\n", val);
>>> }
>>
>> avg is a pointer to double. *avg is a double. If you write
>>
>> *avg / periods
>>
>> your dividing one double value by periods.
>>
>> In your case, avg points to an array of double values. The number of
>> elements in the array is periods. So you have to write a cycle to sum
>> all the periods elements together. At last, you can divide by periods.
>
> That's what I don't know how to do. Write a cycle. It's these little caveats
> in C that confuse me most. Functions I am grasping. Writing cycles not so
> much.
>
"A cycle" might also be called "a loop".
double mean(double * values, int periods) {
double accumulator;
int i;
double average;
accumulator = 0;
for (i = 0; i < periods; ++i)
accumulator += values[i];
average = accumulator / periods;
return average;
}
>>> int main(void)
>>> {
>>> double a[] = 2.2, 4.2, 5.00;
>> ^
>>
>> You are initializing an array. In C you can do that with curly
>> backets {}:
>> double a[] = { 2.2, 4.2, 5.00 };
>>
>>> mean(a, 3);
>> ^
>>
>> In this case you are passing the number of elements of a[] array. I
>> suggest to use a syntax like the following:
>>
>> mean(a, sizeof(a) / sizeof(a[0]));
>
> What's the sizeof(a[0]) mean?
Given:
double a[] = { 2.2, 4.2, 5.00 };
'sizeof a' yields the size of the 'a' array, in bytes. 'sizeof a[0]'
(or 'sizeof *a') gives the size of a single element of the 'a' array, in
bytes. Since a single element is a 'double' in this case, 'sizeof a[0]'
gives the same value as 'sizeof (double)'.
If you divide the size of the array by the size of one of its elements,
you get the number of elements in the array.
>
>> or define a generic macro if you're going to use this syntax in
>> several points:
>>
>> #define SIZEARRAY(a) (sizeof(a) / sizeof(a[0]))
>>
Thus, the above macro gives the number of elements in an array. Same
idea as:
#define COUNTOF(array) (sizeof (array) / sizeof *(array))
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| From | "Bill Cunningham" <nospam@nspam.invalid> |
|---|---|
| Date | 2011-05-28 17:12 -0400 |
| Message-ID | <4de16581$0$1969$bbae4d71@news.suddenlink.net> |
| In reply to | #4938 |
Shao Miller wrote:
> On 5/28/2011 3:12 PM, Bill Cunningham wrote:
>> pozz wrote:
>>> Il 28/05/2011 21:28, Bill Cunningham ha scritto:
>>>> void mean(double *avg, int periods)
>>>> {
>>>> double val;
>>>> val = *avg / periods;
>>>> printf("%.2f\n", val);
>>>> }
>>>
>>> avg is a pointer to double. *avg is a double. If you write
>>>
>>> *avg / periods
>>>
>>> your dividing one double value by periods.
>>>
>>> In your case, avg points to an array of double values. The number of
>>> elements in the array is periods. So you have to write a cycle to
>>> sum all the periods elements together. At last, you can divide by
>>> periods.
>>
>> That's what I don't know how to do. Write a cycle. It's these little
>> caveats in C that confuse me most. Functions I am grasping. Writing
>> cycles not so much.
>>
>
> "A cycle" might also be called "a loop".
>
> double mean(double * values, int periods) {
> double accumulator;
> int i;
> double average;
>
> accumulator = 0;
> for (i = 0; i < periods; ++i)
> accumulator += values[i]; <-
> average = accumulator / periods;
> return average;
> }
I'm a little confused here. accumulator+accumulator=values[i];
The i is being iterated. The accumulator is where the value is being stored
right?
Bill
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| From | Geoff <geoff@invalid.invalid> |
|---|---|
| Date | 2011-05-28 14:26 -0700 |
| Message-ID | <d1q2u6duggde34n7chcqdukjj5havab3m4@4ax.com> |
| In reply to | #4941 |
On Sat, 28 May 2011 17:12:45 -0400, "Bill Cunningham"
<nospam@nspam.invalid> wrote:
>Shao Miller wrote:
>> On 5/28/2011 3:12 PM, Bill Cunningham wrote:
>>> pozz wrote:
>>>> Il 28/05/2011 21:28, Bill Cunningham ha scritto:
>>>>> void mean(double *avg, int periods)
>>>>> {
>>>>> double val;
>>>>> val = *avg / periods;
>>>>> printf("%.2f\n", val);
>>>>> }
>>>>
>>>> avg is a pointer to double. *avg is a double. If you write
>>>>
>>>> *avg / periods
>>>>
>>>> your dividing one double value by periods.
>>>>
>>>> In your case, avg points to an array of double values. The number of
>>>> elements in the array is periods. So you have to write a cycle to
>>>> sum all the periods elements together. At last, you can divide by
>>>> periods.
>>>
>>> That's what I don't know how to do. Write a cycle. It's these little
>>> caveats in C that confuse me most. Functions I am grasping. Writing
>>> cycles not so much.
>>>
>>
>> "A cycle" might also be called "a loop".
>>
>> double mean(double * values, int periods) {
>> double accumulator;
>> int i;
>> double average;
>>
>> accumulator = 0;
>> for (i = 0; i < periods; ++i)
>> accumulator += values[i]; <-
>> average = accumulator / periods;
>> return average;
>> }
>
> I'm a little confused here. accumulator+accumulator=values[i];
>The i is being iterated. The accumulator is where the value is being stored
>right?
>
>Bill
>
It would be better written as:
void mean(double *array, int periods)
{
int i;
double mean;
double sum;
sum = 0;
for (i=0; i < periods; i++)
sum = sum + array[i];
mean = sum / periods;
printf("%.2f\n", mean);
}
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| From | Shao Miller <sha0.miller@gmail.com> |
|---|---|
| Date | 2011-05-28 16:29 -0500 |
| Message-ID | <irrpfj$lhi$1@dont-email.me> |
| In reply to | #4941 |
On 5/28/2011 4:12 PM, Bill Cunningham wrote:
> Shao Miller wrote:
>> On 5/28/2011 3:12 PM, Bill Cunningham wrote:
>>> pozz wrote:
>>>> Il 28/05/2011 21:28, Bill Cunningham ha scritto:
>>>>> void mean(double *avg, int periods)
>>>>> {
>>>>> double val;
>>>>> val = *avg / periods;
>>>>> printf("%.2f\n", val);
>>>>> }
>>>>
>>>> avg is a pointer to double. *avg is a double. If you write
>>>>
>>>> *avg / periods
>>>>
>>>> your dividing one double value by periods.
>>>>
>>>> In your case, avg points to an array of double values. The number of
>>>> elements in the array is periods. So you have to write a cycle to
>>>> sum all the periods elements together. At last, you can divide by
>>>> periods.
>>>
>>> That's what I don't know how to do. Write a cycle. It's these little
>>> caveats in C that confuse me most. Functions I am grasping. Writing
>>> cycles not so much.
>>>
>>
>> "A cycle" might also be called "a loop".
>>
>> double mean(double * values, int periods) {
>> double accumulator;
>> int i;
>> double average;
>>
>> accumulator = 0;
>> for (i = 0; i< periods; ++i)
>> accumulator += values[i];<-
>> average = accumulator / periods;
>> return average;
>> }
>
> I'm a little confused here. accumulator+accumulator=values[i];
> The i is being iterated. The accumulator is where the value is being stored
> right?
The line:
accumulator += values[i];
is similar to:
accumulator = accumulator + values[i];
and not to:
accumulator + accumulator = values[i];
Yes. As its name suggests, the 'accumulator' is accumulating every
value in the array; it's the sum.
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| From | Joe Pfeiffer <pfeiffer@cs.nmsu.edu> |
|---|---|
| Date | 2011-05-28 17:26 -0600 |
| Message-ID | <1bvcwufluj.fsf@snowball.wb.pfeifferfamily.net> |
| In reply to | #4941 |
"Bill Cunningham" <nospam@nspam.invalid> writes:
> Shao Miller wrote:
>> accumulator += values[i]; <-
>
> I'm a little confused here. accumulator+accumulator=values[i];
> The i is being iterated. The accumulator is where the value is being stored
> right?
No, it means
accumulator = accumulator + values[i];
--
"Erwin, do you know what happened to the cat?" -- Mrs. Shroedinger
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| From | Geoff <geoff@invalid.invalid> |
|---|---|
| Date | 2011-05-28 14:20 -0700 |
| Message-ID | <rdp2u6pop1qrg1spa2pb5rltnurclcbqlb@4ax.com> |
| In reply to | #4933 |
On Sat, 28 May 2011 16:12:03 -0400, "Bill Cunningham" <nospam@nspam.invalid> wrote: >> mean(a, sizeof(a) / sizeof(a[0])); > >What's the sizeof(a[0]) mean? It's the size, in bytes, (whatever they are), of the first element of the array "a". It's better than writing sizeof(double) because if you change the declaration of "a" from double a[] to float a[] you don't have to change the calculation of the size. sizeof(a) / sizeof(a[0]) is "the total length of the array divided by the length of any member of the array" (i.e., the count of the members of the array).
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| From | "Bill Cunningham" <nospam@nspam.invalid> |
|---|---|
| Date | 2011-05-29 02:16 -0400 |
| Message-ID | <4de1e503$0$1976$bbae4d71@news.suddenlink.net> |
| In reply to | #4942 |
Geoff wrote:
> On Sat, 28 May 2011 16:12:03 -0400, "Bill Cunningham"
> <nospam@nspam.invalid> wrote:
>
>>> mean(a, sizeof(a) / sizeof(a[0]));
>>
>> What's the sizeof(a[0]) mean?
>
> It's the size, in bytes, (whatever they are), of the first element of
> the array "a". It's better than writing sizeof(double) because if you
> change the declaration of "a" from double a[] to float a[] you don't
> have to change the calculation of the size.
>
> sizeof(a) / sizeof(a[0]) is "the total length of the array divided by
> the length of any member of the array" (i.e., the count of the members
> of the array).
Oh Ok I see.
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| From | Lew Pitcher <lpitcher@teksavvy.com> |
|---|---|
| Date | 2011-05-28 16:35 -0400 |
| Message-ID | <tEwEp.6367$4h1.987@newsfe06.iad> |
| In reply to | #4933 |
On May 28, 2011 16:12, in comp.lang.c, nospam@nspam.invalid wrote:
> pozz wrote:
>> Il 28/05/2011 21:28, Bill Cunningham ha scritto:
>>> void mean(double *avg, int periods)
>>> {
>>> double val;
>>> val = *avg / periods;
>>> printf("%.2f\n", val);
>>> }
>>
>> avg is a pointer to double. *avg is a double. If you write
>>
>> *avg / periods
>>
>> your dividing one double value by periods.
>>
>> In your case, avg points to an array of double values. The number of
>> elements in the array is periods. So you have to write a cycle to sum
>> all the periods elements together. At last, you can divide by periods.
>
> That's what I don't know how to do. Write a cycle.
Bill, you've done it before. Why can't you write a "cycle" (aka a "loop")
this time?
Think
for (....) {/*something*/}
or
while (....) {/*something*/}
or
do {/*something*/} while (....);
> It's these little
> caveats in C that confuse me most. Functions I am grasping. Writing cycles
> not so much.
>
>>> int main(void)
>>> {
>>> double a[] = 2.2, 4.2, 5.00;
>> ^
>>
>> You are initializing an array. In C you can do that with curly
>> backets {}:
>> double a[] = { 2.2, 4.2, 5.00 };
>>
>>> mean(a, 3);
>> ^
>>
>> In this case you are passing the number of elements of a[] array. I
>> suggest to use a syntax like the following:
>>
>> mean(a, sizeof(a) / sizeof(a[0]));
>
> What's the sizeof(a[0]) mean?
Again, you know this.
What does sizeof(int) mean?
What does sizeof(double) mean?
What does sizeof("string") mean?
>> or define a generic macro if you're going to use this syntax in
>> several points:
>>
>> #define SIZEARRAY(a) (sizeof(a) / sizeof(a[0]))
>>
>> In this way, you can modify the number of elements in the
>> initialization, but you haven't to modify the number of elements that
>> will be automatically calculated by the preprocessor.
>>
>> Of course, this is valid only for static allocated array. You you
>> dinamically allocate an array, you are responsible to take its lenght
>> in some variable.
>>
>>> }
>>> p.c: In function `main':
>>> p.c:12: invalid initializer
>>> p.c:12: parse error before numeric constant
>>>
>>> What's it trying to tell me?
>>
>> See above.
>
>
--
Lew Pitcher
Master Codewright & JOAT-in-training | Registered Linux User #112576
Me: http://pitcher.digitalfreehold.ca/ | Just Linux: http://justlinux.ca/
---------- Slackware - Because I know what I'm doing. ------
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| From | "Bill Cunningham" <nospam@nspam.invalid> |
|---|---|
| Date | 2011-05-29 15:50 -0400 |
| Message-ID | <4de2a3da$0$1966$bbae4d71@news.suddenlink.net> |
| In reply to | #5016 |
Lew Pitcher wrote:
> On May 28, 2011 16:12, in comp.lang.c, nospam@nspam.invalid wrote:
>
>> pozz wrote:
>>> Il 28/05/2011 21:28, Bill Cunningham ha scritto:
>>>> void mean(double *avg, int periods)
>>>> {
>>>> double val;
>>>> val = *avg / periods;
>>>> printf("%.2f\n", val);
>>>> }
>>>
>>> avg is a pointer to double. *avg is a double. If you write
>>>
>>> *avg / periods
>>>
>>> your dividing one double value by periods.
>>>
>>> In your case, avg points to an array of double values. The number of
>>> elements in the array is periods. So you have to write a cycle to
>>> sum all the periods elements together. At last, you can divide by
>>> periods.
>>
>> That's what I don't know how to do. Write a cycle.
>
> Bill, you've done it before. Why can't you write a "cycle" (aka a
> "loop") this time?
I know but its been a long long time. I got away from C for a long time
awhile back. Burned out or something. And remember I am a hobyist. I have
other things in my life besides C.
> Think
> for (....) {/*something*/}
> or
> while (....) {/*something*/}
> or
> do {/*something*/} while (....);
>
>
>> It's these little
>> caveats in C that confuse me most. Functions I am grasping. Writing
>> cycles not so much.
>>
>>>> int main(void)
>>>> {
>>>> double a[] = 2.2, 4.2, 5.00;
>>> ^
>>>
>>> You are initializing an array. In C you can do that with curly
>>> backets {}:
>>> double a[] = { 2.2, 4.2, 5.00 };
>>>
>>>> mean(a, 3);
>>> ^
>>>
>>> In this case you are passing the number of elements of a[] array. I
>>> suggest to use a syntax like the following:
>>>
>>> mean(a, sizeof(a) / sizeof(a[0]));
>>
>> What's the sizeof(a[0]) mean?
>
> Again, you know this.
>
> What does sizeof(int) mean?
> What does sizeof(double) mean?
> What does sizeof("string") mean?
>
>>> or define a generic macro if you're going to use this syntax in
>>> several points:
>>>
>>> #define SIZEARRAY(a) (sizeof(a) / sizeof(a[0]))
>>>
>>> In this way, you can modify the number of elements in the
>>> initialization, but you haven't to modify the number of elements
>>> that will be automatically calculated by the preprocessor.
>>>
>>> Of course, this is valid only for static allocated array. You you
>>> dinamically allocate an array, you are responsible to take its
>>> lenght in some variable.
>>>
>>>> }
>>>> p.c: In function `main':
>>>> p.c:12: invalid initializer
>>>> p.c:12: parse error before numeric constant
>>>>
>>>> What's it trying to tell me?
>>>
>>> See above.
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| From | Joe Pfeiffer <pfeiffer@cs.nmsu.edu> |
|---|---|
| Date | 2011-05-29 20:39 -0600 |
| Message-ID | <1bk4d852tt.fsf@snowball.wb.pfeifferfamily.net> |
| In reply to | #5016 |
Lew Pitcher <lpitcher@teksavvy.com> writes: > > Bill, you've done it before. Why can't you write a "cycle" (aka a "loop") > this time? I'm not Bill, but calling it a "cycle" threw me completely. I had no idea what he was talking about. -- "Erwin, do you know what happened to the cat?" -- Mrs. Shroedinger
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| From | Geoff <geoff@invalid.invalid> |
|---|---|
| Date | 2011-05-28 13:46 -0700 |
| Message-ID | <sin2u6lpn35s851tau49f4vaak2351tfal@4ax.com> |
| In reply to | #4924 |
On Sat, 28 May 2011 15:28:24 -0400, "Bill Cunningham"
<nospam@nspam.invalid> wrote:
> I am trying here to calculate a mean of 3 values. I do not understand
>the errors the compiler returned I've never seen them.
>
>#include <stdio.h>
>
>void mean(double *avg, int periods)
>{
> double val;
> val = *avg / periods;
> printf("%.2f\n", val);
>}
>
>int main(void)
>{
> double a[] = 2.2, 4.2, 5.00;
> mean(a, 3);
>}
>p.c: In function `main':
>p.c:12: invalid initializer
>p.c:12: parse error before numeric constant
>
> What's it trying to tell me?
>
It's telling you the array of doubles, a[] was initialized
incorrectly. You must use braces to initialize an array.
The parse error is a secondary effect of the bad syntax of your array
initialization.
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| From | Nobody <nobody@nowhere.com> |
|---|---|
| Date | 2011-05-28 23:06 +0100 |
| Message-ID | <pan.2011.05.28.22.05.43.62000@nowhere.com> |
| In reply to | #4924 |
On Sat, 28 May 2011 15:28:24 -0400, Bill Cunningham wrote:
> void mean(double *avg, int periods)
> {
> double val;
> val = *avg / periods;
> printf("%.2f\n", val);
> }
> }
Note the excess closing brace.
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| From | Ian Collins <ian-news@hotmail.com> |
|---|---|
| Date | 2011-05-29 10:10 +1200 |
| Message-ID | <94da7jFr2iU5@mid.individual.net> |
| In reply to | #4945 |
On 05/29/11 10:06 AM, Nobody wrote:
> On Sat, 28 May 2011 15:28:24 -0400, Bill Cunningham wrote:
>
>> void mean(double *avg, int periods)
>> {
>> double val;
>> val = *avg / periods;
>> printf("%.2f\n", val);
>> }
>> }
>
> Note the excess closing brace.
>
There wasn't one to note in the OP.
--
Ian Collins
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| From | Ian Collins <ian-news@hotmail.com> |
|---|---|
| Date | 2011-05-29 10:09 +1200 |
| Message-ID | <94da4tFr2iU4@mid.individual.net> |
| In reply to | #4924 |
On 05/29/11 07:28 AM, Bill Cunningham wrote:
> I am trying here to calculate a mean of 3 values. I do not understand
> the errors the compiler returned I've never seen them.
>
> #include<stdio.h>
>
> void mean(double *avg, int periods)
> {
> double val;
> val = *avg / periods;
> printf("%.2f\n", val);
> }
>
> int main(void)
> {
> double a[] = 2.2, 4.2, 5.00;
> mean(a, 3);
> }
> p.c: In function `main':
> p.c:12: invalid initializer
> p.c:12: parse error before numeric constant
>
> What's it trying to tell me?
To get a C programming bog and read it.
--
Ian Collins
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| From | Angel <angel+news@spamcop.net> |
|---|---|
| Date | 2011-05-28 22:28 +0000 |
| Message-ID | <slrniu2toc.6e6.angel+news@pearlgates.net> |
| In reply to | #4924 |
On 2011-05-28, Bill Cunningham <nospam@nspam.invalid> wrote:
>
> int main(void)
> {
> double a[] = 2.2, 4.2, 5.00;
> mean(a, 3);
> }
> p.c: In function `main':
> p.c:12: invalid initializer
> p.c:12: parse error before numeric constant
>
> What's it trying to tell me?
That you should get a good tutorial on the syntax of C, and read it.
The error means literally what it says, you initialized your array
wrongly. An array initializer must be between accolades.
--
"C provides a programmer with more than enough rope to hang himself.
C++ provides a firing squad, blindfold and last cigarette."
- seen in comp.lang.c
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| From | Ian Collins <ian-news@hotmail.com> |
|---|---|
| Date | 2011-05-29 10:37 +1200 |
| Message-ID | <94dbp1Fr2iU6@mid.individual.net> |
| In reply to | #4950 |
On 05/29/11 10:28 AM, Angel wrote:
> On 2011-05-28, Bill Cunningham<nospam@nspam.invalid> wrote:
>>
>> int main(void)
>> {
>> double a[] = 2.2, 4.2, 5.00;
>> mean(a, 3);
>> }
>> p.c: In function `main':
>> p.c:12: invalid initializer
>> p.c:12: parse error before numeric constant
>>
>> What's it trying to tell me?
>
> That you should get a good tutorial on the syntax of C, and read it.
>
> The error means literally what it says, you initialized your array
> wrongly. An array initializer must be between accolades.
accolades?
I guess you aren't a native English speaker. In English an accolade is
some form of award or praise!
--
Ian Collins
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| From | Angel <angel+news@spamcop.net> |
|---|---|
| Date | 2011-05-28 22:45 +0000 |
| Message-ID | <slrniu2uo6.6e6.angel+news@pearlgates.net> |
| In reply to | #4951 |
On 2011-05-28, Ian Collins <ian-news@hotmail.com> wrote: > On 05/29/11 10:28 AM, Angel wrote: >> >> The error means literally what it says, you initialized your array >> wrongly. An array initializer must be between accolades. > > accolades? > > I guess you aren't a native English speaker. In English an accolade is > some form of award or praise! Dutch, actually. And here an accolade is one of those curly brace thingies you put around statement blocks and array initializers. :-) According to Wikipedia, it has that meaning in English too, but only in the context of muscial notation. :-) https://secure.wikimedia.org/wikipedia/en/wiki/Accolade_%28notation%29#Lines -- "C provides a programmer with more than enough rope to hang himself. C++ provides a firing squad, blindfold and last cigarette." - seen in comp.lang.c
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