a little mistake

[ash]

i am writing this program (for exercise1-9 in k&r-2nd edition) which
removes extra spaces in string
example- "test string" will be "test string"

#include<stdio.h>
#include<string.h>
#include<conio.h>
main()
{
char str[20],st[20];
int i=0,j=0;
printf("enter string");
gets(str);

while(str[i]!=NULL)
{
if(str[i]==' ')
{ st[j++]=st[i++];

while(str[i]==' ') i++;

}
else
st[j++]=str[i++];
}
st[j]=NULL;
strcpy(str,st);
puts(str);
}

(compiled in turbo c++ for windows version 3.1)
i know there should be other ways to write this program (thats a bad
program ),can someone help me in writing that program in compact way
and give me some logic and tips.
i want to use gcc but i don`t have linux operating system and one
software which allows gcc compiling in windows (cygwin) is not working.
anyone can advice me such a program that allows compiling with gcc in
windows( this is off topic but advices are always welcome).

thankx

[av]

On Mon, 19 Jun 2006 16:57:37 +0000, Richard Heathfield
<in*****@invalid.invalid> wrote:

CBFalconer said:

Tom St Denis wrote:

... snip ...

The fact that on basically every platform 0 == NULL is just an
added bonus.

Making that assumption, in any case where it may matter, is
extremely sloppy programming.

if(0 == NULL)
{
puts("No, it's guaranteed that 0 == NULL.");
puts("This stuff will always be written to stdout.");
}

if stdout is open

[Old Wolf]

Tom St Denis wrote:

When you calloc a structure with pointers, they're VERY LIKELY to be
equal to NULL. this is the "added bonus" I was talking about.

#include <stdio.h>
#include <stdlib.h>

int main()
{
if ( rand() % 12345678 == 7654321 )
printf("tom is an egg\n");

return 0;
}

It's VERY LIKELY that this program will never offend anyone
when run. Does that make it acceptable?

[Dave Thompson]

On Mon, 19 Jun 2006 14:58:58 +0000, Richard Heathfield
<in*****@invalid.invalid> wrote:

The following technique has served me well when creating aggregate objects
of type T:

#include <stdlib.h>
#include "t.h"

T *T_create(int this, double that, long theother)
{
const T blank = {0};
I declare this static. Although a good enough compiler could figure
that for me, it's easy enough not to assume/rely on that.
T *new = malloc(sizeof *new);
if(new != NULL)
{
*new = blank; /* get default static initialisers in place */
new->this = this;
new->that = that;
new->theother = theother; /* override specific fields */

/* all other fields in 'new' have their default values */
}
return new;
}

This way guarantees that *either* the allocation fails (in which case 'new'
is NULL) *or* it succeeds and no member object of 'new' will be
uninitialised.

Alternatively, I might soon start using C99 *new = {.this = etc.} .
- David.Thompson1 at worldnet.att.net

[Frederick Gotham]

Dave Thompson posted:

On Mon, 19 Jun 2006 14:58:58 +0000, Richard Heathfield
<in*****@invalid.invalid> wrote:

The following technique has served me well when creating aggregate
objects of type T:

#include <stdlib.h>
#include "t.h"

T *T_create(int this, double that, long theother)
{
const T blank = {0};

I declare this static. Although a good enough compiler could figure
that for me, it's easy enough not to assume/rely on that.

I would think that that would be misuse of the "static" keyword.

The purpose of static variables within functions is that we can retain a
value until the next invocation of that function.
--

Frederick Gotham

[Chris Dollin]

Frederick Gotham wrote:

Dave Thompson posted:

On Mon, 19 Jun 2006 14:58:58 +0000, Richard Heathfield
<in*****@invalid.invalid> wrote:

The following technique has served me well when creating aggregate
objects of type T:

#include <stdlib.h>
#include "t.h"

T *T_create(int this, double that, long theother)
{
const T blank = {0};
I declare this static. Although a good enough compiler could figure
that for me, it's easy enough not to assume/rely on that.

I would think that that would be misuse of the "static" keyword.

Why? `static` says there's just the one `blank`, rather than a new
`blank` each function call. That seems to be just fine.
The purpose of static variables within functions is that we can retain a
value until the next invocation of that function.

That's not /the/ purpose. That's /a/ purpose. Another purpose is to
hide a constant from sibling functions.

--
Chris "dynamic" Dollin
"People are part of the design. It's dangerous to forget that." /Star Cops/